4 Minerals and Clusius’s Saxonian relations

In the following sections we continue to explore Clusius's interests and activities relating to non-living naturalia by focusing on specific categories of intriguing inorganic objects that emerge from documents concerning Clusius. First the basic category of such naturalia will come into spotlight: valuable minerals in their natural form¹ that can be either metallic (for instance silver ores) or non-metallic (for instance gemstones). In the following I will use the word “mineral” in this sense (that is, from the collector's perspective, and not in the sense of “mineral kingdom” as opposed to “animal” or “plant kingdom”). In sixteenth-century Latin correspondence the word metallica is frequently used in this sense.² What we call minerals could be in Agricola's terms “metals”, “congealed juices”, “composite objects” and most types of “stones”. “Stones” with a curious shape and special types of earth do not belong to our category minerals; these will also be interesting for Clusius and his contemporaries, and the relevant sources deserve to be treated separately, in the later sections of this study.

Minerals were standard representatives of the inorganic part of nature in sixteenth-century “museums” or “Wunderkammern”, and have been sought for by private collectors well into our modern times. Beyond possible practical uses and economic value, they are beautiful to look at; these coloured, translucent bodies, shining and glimmering, often displaying splendid geometrical forms, represent in a most spectacular way the “wonders of nature” ardently sought after by a host of Renaissance scholars. In Clusius's correspondence, specimens of minerals appear several times as highly valued objects requested or sent by fellow men of letters – and interestingly, they were almost always asked for or sent by friends living or staying in Saxony (see the map, Fig. 10, at the end of the study), a region rarely mentioned in the Clusius literature.

The Electorate of Saxony, with Wittenberg among its universities and with the Erzgebirge (Ore Mountains) among its mountains, stood out from the states of the Holy Roman Empire not only as the cradle of Reformation, but also as the richest principality, with a fast developping industrial and mining complex. The region had grown famous for its silver quarries as early as the twelfth century; while from the end of the fifteenth century onwards the pace of opening new quarries in the Ore Mountains region increased. Beyond silver, the production of which remained the most important line, a number of other resources were also produced including metals or metallic minerals like gold, copper, iron, lead, tin, zinc or cobalt, but also materials that were categorised under “stones” or “earths”, like clay, limestone or granite.³ In close interaction with the development of the mining industry, Saxony became central to the birth of the geosciences or “mountain sciences”,⁴ hallmarked by the already frequently mentioned Georgius Agricola, the humanist and naturalist whose oeuvre determined the development of these sciences for centuries. In The History of Mineral Collecting⁵ (a standard review volume of the field), half of the highlighted first-generation, mid-sixteenth century collectors come from Saxony: this indicates well the region's role in the history of mineralogy in the broader sense.

The governmental support of mining received a new impetus under Elector Augustus (r. 1553–86) who had a firm control over the related branches of the economy. He himself was an avid collector of underground treasures: his Kunstkammer, that came to include more than ten thousand items, had a large section of Saxon minerals.⁶ In general, the elector supported the arts and sciences and, from a confessional point of view, the “Philippists”: the circle of Wittenberg intellectuals with a Melanchthonian background, including Caspar Peucer, Hubert Languet or Georg Cracow, had a marked influence at the court.⁷ The most powerful intellectual was Johann Jenitz, the chief secretary who stood always at his ruler's side, and wo even handled his correspondence.⁸ As will be seen, the intellectual elite around the elector will greatly overlap with the circle of Clusius's Saxony-based friends or contact persons.

The following investigation will adumbrate the role of minerals in Clusius's correspondence and relations, and will at the same time throw light on how Clusius liaised with members of the Saxonian elite. The overview will not be exhaustive, all the less so since we can only rely on sporadically surviving sources and little previous literature. Clusius's Saxonian relations have not been directly addressed in scholarship, most of the relevant letters have not been edited, for several correspondents there is hardly any literature at all, and the identification of sixteenth-century Latin mineral names is also problematic on occasion.⁹

At the present state of research the earliest pieces of evidence of inorganic naturalia sent to Clusius come from the correspondence between Clusius and Kaspar Peucer (1525–1602), the renowned church reformer, humanist and naturalist. Peucer studied and then lectured, among other subjects, on medicine at the University of Wittenberg; in the 1560s he became probably the most influential professor at the university, and one of the confidential men of letters of Elector Augustus (at least from 1563 to around 1574).¹⁰ Clusius got acquainted with him already as a student in Wittenberg, where he stayed in the second half of 1549; indeed it is even possible that he was a guest staying over in Peucer's house.¹¹ It was in that short Wittenberg period that Clusius made friends with Hubert Languet (1518–81): their common mother tongue (French, amidst a predominantly German milieu), their common humanist interests and their similar open-minded character resulted in a close and lasting friendship between them.¹² In 1559 Languet entered the service of the elector as diplomat responsible for Western, notably French matters; he would become a key figure in Clusius's relations to the Saxonian elite.

It is not specified who the nostri, “our men” or “our circles”, were; it must certainly have meant Peucer's elite circles in Wittenberg and beyond. Gupilius is Jacques Goupyl (ca. 1525–1564), professor of medicine in Paris, one of Clusius's teachers. Peucer does make Clusius feel that he is asking quite a favour – indeed, from the way he speaks, it is hard to imagine that he acted fully of his own accord, without Clusius asking for certain specimens in any of his (now lost) letters. No wonder that Goupyl, the professor of medicine – and thus Peucer's colleague in Paris – is included among the addressees of the „metallic” package: after such valuable things were at last collected and ready to be sent to Paris, Peucer used the occasion to build his network by involving more than one man. The outer circumstances of the transaction also indicate that it was a fairly special occasion: the whole procedure lasted around a year and a half¹⁸ and the transfer needed a safe route and trustworthy mediators.¹⁹

Beyond the material value of the items being sent, which was undoubtedly high, it was also noteworthy that Clusius received minerals in exchange for seeds and herbs. The most customary and typical objects of exchange in the correspondence between Clusius and another physician / naturalist (like Joachim Camerarius the Younger, Georg Purkircher, Pascal le Coq and so on) were botanical naturalia, which Clusius used both to send and receive. Was the pattern „minerals for plants” ever repeated? Still in 1562, Clusius received another offer from Saxony. In a letter dated December 1, 1562, Languet called the attention of his friend (who was already back in the Southern Netherlands) to Johann Jenitz and Valerius Cracow, „chief secretaries” of the elector,²⁰ who possessed great gardens in which they collected rare plants. They learned that Clusius sent seeds or plants via Languet to Peucer, and now they, too, would like to receive some; Languet had already warmly recommended Clusius to them. “They promised that if they received something outstanding from you, in turn they would send any mineral that you [Clusius] indicate would be precious to you.”²¹ Apparently, they learned from Languet or Peucer that Clusius liked minerals, otherwise they would not have offered metallica right at the beginning. Unfortunately, no further letter seems to have survived that would inform us about the development of this connection with the high dignitaries – and thus with the court –, but Clusius certainly did not miss the opportunity for networking in general and acquiring naturalia in particular. Valerius Cracow was a confidential chamber secretary, and Jenitz, as seen above, the right hand of the Holy Roman Empire's richest elector. Languet alludes in the letter itself to the great prospects that such connections have in store.²²

From the year 1566, too, there survived relevant documents with more explicit traces of Clusius's interests. In the introduction to Part I of this study I presented his letters to Johannes Crato and Thomas Rehdiger, both dated November 29, 1566. Clusius shared with Crato how Gessner's De omni rerum fossilium… liber aroused his enthusiasm for “stones”; he asked specimens of “eagle's stones” from Rehdiger, and in later letters to Crato he requested from Transylvania “Saint Ladislaus's coins”, special round stones that look like petrified gold coins (see the next section). The Wrocław-based Crato stood close to several “Philippist” scholars in Saxony like Peucer or Joachim Camerarius the Elder, and in 1561 he, as well as Peucer, seems to have supported that Clusius be chosen as the praeceptor of Thomas Rehdiger.²³ The young Wrocław patrician was brought from Wittenberg to Paris by Languet, who appears to have been in the mediator's role in relation to Crato and the Rehdigers, too. Clusius certainly saw and learned about minerals and non-living naturalia in general in a medical context first, both in Wittenberg in 1549 and in Paris between 1560 and 62 (his Antidotarium from 1561, which included descriptions of inorganic naturalia, has already been mentioned²⁴), but the letters from his correspondence referred to in this section do not indicate in any way that he needed the specimens for medical purposes. Rather, the relevant passages adumbrate a general, scientific interest, in Agricola's and Gessner's spirit. He had most probably been familiar with the relevant works of Agricola since his day in Wittenberg or Paris²⁵ (the only reliable source as to the books he owned is the book catalogue made after his death in 1609, and according to this, he possessed at that time at least Agricola's Bermannus and De re metallica, and also Christoph Entzelt's De re metallica).²⁶ As he wrote in his 1566 letter to Crato, Gessner's work “once again aroused” his enthusiasm “which had been almost asleep.”²⁷ This manner of expression, together with the above discussed passages from letters written in 1560–62, point toward the early 1560s (or before) as the beginning of Clusius's significant concern for metallica. Finding places in Saxony feature most frequently in Agricola's De natura fossilium and De re metallica, as well as in Gessner's treatise, and this may have easily contributed to Clusius's orientation towards Saxony and its treasures.

The clearest pieces of evidence of this orientation come from his correspondence with Ludwig Camerarius (1542–82), son of Joachim Camerarius the Elder and younger brother to Joachim the Younger. While quite a lot is known to scholarship about Joachim Jr., a naturalist of European renown living in Nuremberg, and his relationship with Clusius – around 200 (!) of his letters to Joachim Jr. have survived –,²⁸ we are far less well informed about Ludwig.²⁹ At any rate, nine letters he wrote to Clusius are extant, and the frequent references to him in the correspondence between Clusius and Joachim Jr. also attest to his and Clusius's familiar relations. In the mid-1570s Ludwig worked as a physician in Annaberg, one of the central mining towns of the Electorate, but he had also visited Saxony several times before and was well connected to its intellectual elite, as is clear from Ludwig Camerarius's first surviving letter to Clusius. According to this letter from July 8, 1566, Clusius had informed Languet that he yearned to learn about and explore minerals in Germany. Ludwig (who knew Clusius at least since May 1565³⁰ heard about Clusius's inquiry from Languet, and now offers his support in the matter. He knows certain scholars in Misnia, the core region of Saxony,³¹ who earned great fame for their knowledge in this field. They acquired considerable amounts of such treasures; it is not easy to access any of them, but if Ludwig offers to them equally valuable presents in Clusius's name, they would certainly send something. They are all delighted with exotic plants and diligently cultivated their gardens…³² In his letter Camerarius enumerates six scholars (sometimes with their profession or the place of residence) who have been identified as follows:

1. -Kaspar Peucer („with whom I know you are acquainted”, sais Camerarius);
2. -Georg Aemilius (Oemler, 1517–1569) from Stollberg, a man of letters principally known for theological works (he, too, was disciple of Melanchton), also a botanist;
3. -Georg Fabricius (1516–1571), humanist and also a naturalist, rector of the school of Meissen;
4. -Christoph Leuschner (1521–1574), also from Meissen;³³
5. -Johannes Kentmann (1518–1574), city physician in Torgau, already mentioned as an author in Gessner's De omni rerum fossilium genere;
6. -Joachim Kreich (d. 1575), apothecary in Torgau.

Camerarius provides this enumeration as consisting of scholars “who acquired treasures ex rebus metallicis”, but at the same time this is a good cross-section of that part of the Saxonian elite who were naturalists in whatever sense of the word. Several of them were friends of Agricola or Gessner, and / or were frequently mentioned in the works of these two leading naturalists.³⁴ They are known to modern scholarship to varying extents; and since they do not appear in further surviving letters – except for Kreich –, there is no need here to throw further light on them. What is important for us at this point is that a circle of naturalists existed in Saxony who seem to have exchanged minerals or at least information on minerals (as referred to in the letter itself³⁵), and to this circle Clusius was about to connect via Camerarius.

This time it is certain that Clusius was the one who requested metallica, and that specificly from Germany or Saxony. He wrote to Languet (still in electoral service), and asked for (information about) minerals „extracted in Germany” – and by this he meant mainly metallic minerals, as will be seen. Again, we can only make inferences about Clusius's side of the correspondence from references and notes in Camerarius's letters. According to a letter written in July 1566, Johannes Kreich presented Camerarius earlier with “tiny nuggets of pure silver” which the latter sends now to Clusius “so that you would remember me”. Kreich will give more and larger pieces in exchange for seeds, so the matter is up to Clusius, whom Camerarius himself will also commend to the Torgau apothecary's attention.³⁶ As could be expected, Clusius indeed sent seeds: Camerarius thanks him in his next letter for the semina sent to Kreich.³⁷ Our Low Countries naturalist had a good chance that Kreich gave something metallic in exchange: not only Camerarius seems to have recommended him, but Kreich was also closely related to Peucer.³⁸ In his reply to Camerarius, Clusius must have reinforced that such exchanges were to his liking, because Camerarius answered on December 20 that when he returns to Germany some half a year later, he “would not forget” Clusius, “especially [in connection] with those who I think can contribute something to that treasury of yours, if I may use this expression.”³⁹ Camerarius's use of the word thesaurus is noteworthy here: in his letter of July 1566 he used it in a context referring the quantity and great value of the accumulated metallica.⁴⁰

The importance of the matter to Clusius is made more probable by his notes on Camerarius's letters, according to which he replied within a few days both to the three above mentioned letters from 1566 and the next group of letters that survived (from between 1569 and 1571⁴¹). The Saxonian side, however, was not so eager to react. On August 1, 1569, Camerarius excuses himself for neglecting the correspondence with Clusius, one of the reasons being that he was not sent any minerals. He writes from Leipzig, “I would have gladly sent something special from the minerals extracted in our region, if I had received anything from my friends according to their promise.”⁴² Camerarius himself, at any rate, tried his best and sent what he could.⁴³ He enclosed with the same letter in 1569 a ring that he had recently received, “made of lead-coloured rough pure silver, with pure red silver in place of the gem”. The ring was made from one nugget, without the help of fire.⁴⁴ Both the argentum plumbei coloris (probably today's argentite) and the argentum rubrum (see Fig. 1a–b; probably pyrargyrite, dark red silver, but can also be proustite, light red silver) are types of silver known in contemporary natural history; Agricola remarks in connection with a Saxonian finding place (Schneeberg) that argentum rude rubrum can serve as a beautiful transparent gem.⁴⁵ On January 22, 1570, Camerarius sent „a sort of limestone in the shape of peas”, that can be found in Karlsbad (Karlovy Vary), and some coins of “no value”.⁴⁶ Gessner also describes this limestone in his 1565 treatise, claiming that it is like “drops turned into pea-shaped stones”⁴⁷ (see Fig. 3b in the next section), and he, too, gives Karlsbad as the finding place (thus Camerarius may have gathered the piece of information from Gessner's work). Today we call this mineral dripstone.

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a. “Argentum rude rubrum” in Aldrovandi (1648, 77). b. Pyrargyrite⁴⁸

Citation: Hungarian Studies 37, S; 10.1556/044.2023.00243

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Our sources regarding the contact which apparently continued throughout the 1570's between Clusius and Ludwig Camerarius are mostly references in the correspondence between Clusius and Joachim Jr.⁴⁸⁴⁹ Altogether they seem to imply that botanical naturalia and books were dominant issues in the correspondence, but metallica also seem to have remained an important topic; all the more so since Ludwig moved to Annaberg.⁵⁰ On July 8, 1577, Clusius mentions to Joachim Jr. that Ludwig wrote to him about a mine recently opened up nearby, whence he sent to Clusius a “little present”.⁵¹ Clusius felt obliged to return the kindness with a rare bulbous plant.⁵² According to Ludwig's letter of January 21, 1578 to Clusius (the only letter surviving from their direct correspondence in this period) the Annaberg naturalist sent a box⁵³ containing various minerals “extracted from our mountains”, principally fragments of metals – silver, copper, lead and tin – as examples of durable materials quite resistant to fire, but also two hardly identifiable specimens which Camerarius could only circumscribe.⁵⁴ The one is a fragment of stone that has a flowery scent and can be found dispersed in the nearby fields;⁵⁵ the other is a petrified liquid that merits the name ‘pseudo-diamond’ due to its outer appearance and hardness.⁵⁶ The whole passage has an aura of scientific interest: Camerarius seems to have done more than simply collect or forward – he seems to have studied and even experimented with such metallica.

Looking at the kinds of minerals that we know to have been mentioned or sent by Camerarius to Clusius, one can see that metallic minerals dominate, which probably mirrors their greater availability in Saxony, or Clusius's greater interest in such minerals, or both. Already in his letter of July 8, 1566, Camerarius specified Chalcytis, Genera Vitrioli, Mysi item et Melant as minerals extracted near Stollberg. In modern terms these are various iron sulphates of different colours⁵⁷ which may be found in their natural state in stone-like form as metallic ores. Their mention by Camerarius may have been accidental, nevertheless “vitriols” or sulphates will continue to appear in later documents related to Clusius. Camerarius sent various kinds of silver, the most important resource of Saxony, at least three times (a tiny nugget in 1566, a ring in 1569 and a fragment of silver ore in 1578); furthermore he also sent other metallic fragments (at least in his 1578 letter), as well as coins.

In general, Clusius's relationship to Ludwig Camerarius – as appears especially from the 1578 letter – had much in common with his relationship to Achilles Cromer whose two letters from 1580 have already been discussed in Section 3. Beyond the usual aspects of humanist-naturalist correspondence – such as an exchange of botanical naturalia, information on friends, books, and so on –, a specific feature was the occasional sending of non-living naturalia, principally metallic minerals, from the central mining regions of Europe. The marked scientific interest for metallica on the part of Camerarius and Cromer is also a common characteristic.

From the 1580s and 1590s few sources seem to have survived that would allow us to draw conclusions about Clusius's attitude to minerals. The exchange of naturalia was not restricted to botanical specimens in this period; however, in such letters related to metallica that I could find it is not Clusius who requested or was presented with such objects, but others, and Clusius played a different role in these transactions. Let us now see an example from 1586, a case quite telling from the perspective of knowledge transfer and of the way in which the humanist-naturalist network functioned when it came to exchange of scarcely available naturalia. On February 20/28, 1568, Gian Vincenzo Pinelli asked Clusius's help in procuring specimens and information about various inorganic naturalia.⁵⁸ Pinelli (a key figure with regard to Clusius's Italian contacts, as seen before⁵⁹) is known to have been a collector of non-living naturalia, among other things.⁶⁰ According to the letter, (1) he needed a fragment of basalt.⁶¹ Agricola, who probably coined the term “basalt” itself,⁶² had remarked in De natura fossilium that it can be found at Stolpen, not far from Dresden (the capital of Saxony), and that the bishop's castle had been built on this kind of “marble”.⁶³ Drawing on Agricola and a letter by Kentmann, Gessner provided in his 1565 treatise a detailed description of basalt. He, too, pointed out its specific form (clearly visible in the illustration that he included, see Fig. 2) and its hardness (also due to metal ingredients).⁶⁴ In his 1586 letter, Pinelli explicitly refers to this passage in Gessner, mentioning even the page number, and the Saxonian finding place; he names a certain “Carlo Th.” who can help to procure it, and asks Clusius to mediate in the matter. (2) Pinelli also wanted to know where certain types of Cadmia⁶⁵ can be found in Germany. Cadmia was a general name for zinc compounds, and such items were found in nature as cadmia fossilis or metallica. However, Pinelli only needed Cadmia fornacum, botryitis, placitis or ostracitis, zinc oxides formed in furnaces. His source of information was certainly an Agricola passage where all these types of minerals are described.⁶⁶

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Basalt in Gessner (1565, De rerum…, 21r)

Citation: Hungarian Studies 37, S; 10.1556/044.2023.00243

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Clusius, still based in Vienna in 1586, received the letter on March 16, and wrote to at least two persons, Carolus Tettis (who is certainly the “Carlo Th.” mentioned by Pinelli) and Antonio Cappa.⁶⁷ We know this from a letter written to Clusius by Johannes Brambach from Dresden, dated August 31, in which Clusius referred to both men in his reply.⁶⁸ Brambach (1528–93) was brother-in-law to Johannes Kentmann and a physician to Elector Augustus, until the latter's death (on February 11 of the same year). In the beginning of his letter, Brambach excuses himself saying that they cannot entirely fulfil Clusius's request, because the furnaces had been moved away; nevertheless, “they” would try their best to meet expectations in the future. For the time being, Brambach sends (beyond valuable things sent by Antonio Cappa) Calcitis and Mysi from Goslar,⁶⁹ that had been sent to him by Andreas Baccharius, physician to Julius of Braunschweig⁷⁰ and his son. Added are beautiful fragments of marble, found and prepared by Giovanni Maria Nosseni (leading architect and sculptor at the court⁷¹). Furthermore, Brambach refers to works which can serve as sources of information about Cadmia: Gessner's De omni rerum fossilium genere, Agricola's works about the subterranean world and a summary about the kinds of Cadmia written by himself. Indeed, there is a one-page writing De Cadmiae speciebus attached to the letter, in Brambach's hand. The other parts of the letter itself concern mainly botany; they expect various plants from Clusius. The latter's note indicates that he received the letter in Vienna, on December 6, together with a box (containing the naturalia) and a letter by Cappa.⁷²

To be sure, it was not only for geographical or practical reasons that Pinelli chose Clusius as mediator; he probably knew about the Vienna-based naturalist's experience with metallica and/or his Saxonian relations. As we can see, Clusius' request had indeed been heard. Several intellectuals of the Saxonian court circles took efforts to send valuable information and specimens. We do not know how Clusius had formulated his mediatory requests in his letters, but Brambach replied in a most respectful way, and the minerals were addressed in part to Clusius himself. Earlier Saxonian connections and exchanges, as well as his growing fame as a botanist (from whom rare plants could be expected) must have played a role in this.

Objects requested from Clusius were not restricted to botanical naturalia: from his network, which grew quite extensive by the 1590s, several examples can be mentioned when he, Clusius, was asked for minerals. In 1591 Ulisse Aldrovandi⁷³ inquired via Johannes Bachofen-Echt whether Clusius had any previously unknown specimens either of living or of non-living naturalia.⁷⁴ In the same year, Jacques Garet Jr., a merchant apothecary who was Clusius's foremost informer about exotic naturalia,⁷⁵ asked in one of his letters sent from London whether his friend (then in Frankfurt-am-Main) could perhaps send certain minerals, as well as, perhaps, an instrument used for drilling holes into pearls.⁷⁶ Jacques Plateau,⁷⁷ who was another frequent correspondent of Clusius and owned a museum with a wide spectrum of naturalia and artificialia, broached mineral-related matters in at least four of his letters to Clusius in the 1590s. As he put it in April 1590, “I do not doubt that your cabinet contains various sorts of minerals, marine shells, drugs, exotic seeds and other rarities coming from the Indies and a number of other regions.” He stated that he would be glad to receive something that happens to be in surplus, and promised similar rarities in return.⁷⁸ He repeated the request in two further letters,⁷⁹ all the more so since his correspondent seemed responsive: that same April of 1590 Clusius sent him pieces of “silver ore”⁸⁰ (which could have easily originated from Saxony, as seen above). Minerals also appeared among the things offered in return by Plateau; in 1598 he even offered a detailed list of the contents of a package he had received from Christiaan Porret⁸¹ – specifying a number of gems and crystals, strange stones and shells –, obviously because he thought Clusius was interested in them.⁸²

The above examples reinforce that the contemporaries did not pigeonhole Clusius as a botanist, but regarded him rather as a humanist-naturalist with several concerns beyond botany; several men of letters looked on him as a scholar who was also interested in and/or possessed valuable non-living naturalia. Still, in the absence of relevant letters by Clusius himself, his attitude at least to minerals in the second half of his life remains a question. It is conspicuous that no case is known from this period with a definite request on the part of Clusius; instead, in the above examples we find him either in a mediatory role or as a potential “provider”. It is also telling that, as we saw in Section 2, Clusius rejected the offer made by the Leiden curators to lecture on non-living naturalia, although this may also have had other reasons than the lack of interest. However, before drawing general conclusions, we first need to discuss examples related to strange stones and special types of earth – this will be the subject of Sections 5 and 6.

Our overview of cases with minerals in Clusius's correspondence overlapped with a partial overview of Clusius's Saxonian relations. Several questions remain open, but some conclusions can already be drawn at this point. First, correspondents based in Saxony formed an important section of Clusius's Europe-wide humanist-naturalist network. Beyond certain direct relations (Peucer, Languet, Ludwig Camerarius) he was also in some sort of contact with several members of the local elite (Jenitz, Kreich, Brambach, Cappa and so on). The circle of these men of letters overlapped with the Saxonian court, and Hubert Languet definitely played a key role in creating and maintaining Clusius's Saxonian relations. Second, exchange of minerals formed an integral part of naturalists' exchange with this region, in line with the local conditions; Saxony's richness in such resources could even be a key factor in Clusius's orientation towards this area in the 1560s. The pattern “minerals for botanical naturalia” seems to have been frequent in naturalist exchange with scholars based in Saxony.⁸³ Third, while minerals were valuable from several perspectives – economical, medicinal, scientific –, it is definitely the scientific/aesthetic aspects that seem to have been dominant in the above discussed exchanges, that is, the scholarly collector's attitude.

5 Messengers from the distant past: fossils and other strange “stones”

Stones or stony materials found in nature that have a peculiar form and resemble something familiar – a geometrical figure, artificial object, plant or animal – have always intrigued people, and received enhanced scholarly attention in the sixteenth century.⁸⁴ Such objects were already discussed to some extent in the first general overviews of res metallica or fossilia (in our terms, non-living naturalia), in Agricola's and Entzelt's⁸⁵ works, but it was Gessner's 1565 edition De omni rerum fossilium genere in which they received considerable focus (mainly in Kentmann's and Gessner's treatises). Gessner's classification of fossilia was based on outer appearance, and it was „stones”, lapides that showed the greatest variety in terms of shape, displaying curious similarities with living beings or geometrical figures; it is characteristic of the role of “stones” in Gessner's work that Clusius too, referred to it as libellus de lapidibus in an already discussed letter from 1566.⁸⁶ The number of woodcut illustrations in the treatise were very helpful in attracting the attention of the public, and later publications about non-living naturalia – like Bauhin's, Imperato's or Aldrovandi's⁸⁷ – contained even more illustrations on strange stones. Stones similar to (parts of) plants or animals were especially mysterious: are they a joke of nature, or were they really once living beings? In Section 3, in connection with Cromer's experience about a fossil tree in the Zuckmantel mine, opposing sixteenth-century theories about the origin of what we today call fossils were already discussed: it was debated whether they were born by means of a certain vis plastica of nature or were living beings turned into stones through various processes. It was also mentioned that Agricola and Gessner do not seem to have taken a clear stance in such questions, although they seem to have been inclined to consider the specimens in question as ancient plants or animals somehow turned into stone. Agricola speaks about some findings of plants and animals petrified by the succus lapidescens (but also allows that certain things can be born inside the earth), and Gessner also sometimes uses the expression “turned into stone” (e.g. conversa in lapidem), without further explanation.⁸⁸

Modern scholarship mostly focused on the above mentioned sixteenth-century review works on non-living naturalia, and actual discussions about and exchange of such naturalia between scholars received much less attention. These natural historical books include mentions of specific items sent by specific scholars – even passages from letters are sometimes quoted –, but extant correspondences (surviving mostly in manuscript) provide many more examples, at least in Clusius's case. For a clearer picture of contemporary concerns about fossil specimens, related letters of the respublica litteraria have to be definitely included in the investigations. Was the share of curious „stones” significant in the exchange of naturalia in the Republic of Letters in general, and in Clusius's correspondence in particular? What kind of strange stones did these men send to each other? How were they called, classified and discussed? What do these cases tell us about the reception of the great natural historical works of the mid-sixteenth century?

Certain “stones” with a curious shape requested or received by Clusius have already been mentioned earlier in this study. In November 1566 he asked for aetites, eagle-stone, from Thomas Rehdiger, who was then in Valence (Fig. 3a shows the illustrations of aetites in Gessner's De rerum fossilium… genere, the treatise that greatly inspired him).⁸⁹ In January 1570, he received a piece of limestone “in the shape of peas” from Ludwig Camerarius (Fig. 3b) – in fact, dripstone –,⁹⁰ and in 1600 he sent similar piselli petrificati (together with many other specimens) to Imperato and Pona, as will be seen later. Let it be mentioned here that Clusius wrote about bezoars, too, and received actual specimens. The bezoar “stone” is a borderline case from the perspective of the question we are investigating: on the one hand, certain kinds of it remind one of gemstones, on the other hand it originates in animal intestines, and this organic origin was already known in the sixteenth century. It was mostly valued for its medicinal properties (notably as an anti-poison), and seems to have appeared in sixteenth-century writings (theoretical works and correspondences) in a medical rather than a „wonders of nature” context. When Clusius translated the third part of Nicolaus Monardes's work on the medicines of the New World, he added a one-page note (plus illustrations) to the Spanish physician's general description of the bezoar about various specimens that he had seen, including three pieces that he himself had received from Francis Drake in 1581.⁹¹

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a. Aetites in Gessner (1565, De rerum…, 10v). b. „Pisolythum” from Karlsbad, in Gessner (1565, De rerum…, 71v)

Citation: Hungarian Studies 37, S; 10.1556/044.2023.00243

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This is not the only time Clusius summarises a Hungarian folk legend; he narrates this legend of Saint Ladislaus (László), king of Hungary (1077–95) in the Nomenclator of Hungarian plant names, too, together with other sagas.⁹⁴ Whatever Clusius believed about the legend itself, he seems to have suspected that those were extraordinary stones, perhaps of a metallic material (other “stones”, too – like hematite – turned out later to be metals). Clusius could not know what modern science does – that what the general folk called “Saint Ladislaus's coin” had once been living organisms. These are in fact nummulites, fossils of a group of single-celled eukaryotes, huge when compared to other single-cell creatures, living a few thousand million years ago. That is why they are so flat and circular (see Fig. 4)⁹⁵ They had grown to the visible size of around 1–5 cm and are indeed of a grey, yellowish or brownish colour. In some rare instances spiral-like lines may also be faintly perceived on them, and this may have triggered beliefs about ancient coins or characteribus incognitis, to use Clusius's words.

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“Saint Ladislaus's coins” (Nummulites)

Citation: Hungarian Studies 37, S; 10.1556/044.2023.00243

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Clusius repeated his request three weeks later,⁹⁶ after which point only Crato's answers survive concerning the matter, who informed his friend about the “lapilli” on May 29, July 12, August 31, September 24 and October 11.⁹⁷ At first Crato is sceptical about Clusius's request, he has “never seen” such coin-like stones and “always considered it a tale”, nevertheless he offers to charge with the task one of his acquaintances, a physician residing in Vienna.⁹⁸ The next letter reveals this physician to have been Thomas Jordanus,⁹⁹ then lecturer at the university. Since he was originally from Kolozsvár (today Cluj-Napoca) and could provide the “little stones” within a short time, Crato had them at his disposal by July 12¹⁰⁰ (because of the legend, Clusius and his friends associated the “Saint Ladislaus's coin” with the mountains near Kolozsvár, although in fact they could and can be found in other parts of Europe, as well¹⁰¹). Later Crato was expecting further such stones and further information on them, although he was a little surprised at Clusius's curiosity, since the stones' “form shows satisfactorily” that they are simply born and grow underground¹⁰² (a reference to nature's vis plastica). Clusius's enthusiasm and curiosity embracing the whole of nature was not generally shared by the contemporary literary republic, and this is clearly discernible from the contrast provided by Crato's letters. He declares to Clusius that he, on his part, does not have a “universal and infinite desire to learn”, he is rather interested in practical, useful knowledge.¹⁰³ He does not want to burden his messengers, travelling on horse-back, with too many such stones.¹⁰⁴ By October, however, he seems to have picked up some of Clusius's enthusiasm: “my thoughts keep revolving around the little stones” – he expects to receive some and learn more about them.¹⁰⁵

Clusius thus must have received at least one (fragment of a) “Saint Ladislaus's coin” by September 1567.¹⁰⁶ It is not known what he thought about it in the end, and no one in his circles was in the position to discover the truth regarding the object's origin. Clusius, who later found a lythoxilon (see below) and contributed to the beginnings of palaeontology, was in fact holding in his hand a once living eukaryote. What is sure is that he could not know the real tale behind it – which would have intrigued him even more than Saint Ladislaus's tale – about life on Earth millions of years ago. In his time, assessments about the age of the Earth (the time after Creation) revolved around 5000 years.

In his later life, however, Clusius had several occasions to hold in his hand „stones” whose similarity to well-known plants or animals was clear, and which thus allowed him to muse on their possible origin as living beings. In the following we will review such cases – that is, fossils in the modern sense which he obtained or was informed about. As for plants, one case has already been discussed: in May 1580 Achilles Cromer reported about remnants of a tree enclosed in rocks, found in one of the Zuckmantel mines; and according his letter of July 1580, the miners saw several such ancient trees.¹⁰⁷ Cromer could only send information on the findings and discussions surrounding them, but no fragments of the trees themselves. However, Clusius did have pieces of fossilised wood, and he found at least one such piece himself. This is the piece of Quercus cerris that he found in Vashegy (Eisenberg) in Hungary. The finding is already known to scholarship, but Cromer's letters allow us further to contextualise the episode.

From 1577 onwards, at the latest, Clusius often visited the Hungarian aristocrat Boldizsár Batthyány, a most inspiring patron and friend,¹⁰⁸ and made field trips using Batthyány's castles as his base. In the hill of Vashegy (in German: Eisenberg), between Batthyány's two most important castles at that time, Szalónak and Németújvár (now Stadtschlaining and Güssing, both in Austria), he found fragments of a petrified “Lithoxylon” (a Quercus cerris) whose veins, rings and other features could still be seen. As Clusius relates in Pannonian Flora, “I not only observed” such fragments “that were dug out, and owned not only as presents from… Boldizsár Batthyány…, but I myself also collected such on the slope of… the hill of Eisenberg…”¹⁰⁹ Modern scholarship has already expressed its appreciation for Clusius's skills in xylotomy and openness to palaeontology which helped, first, to recognise the object as a fossil plant, and second, to identify it as Quercus cerris.¹¹⁰ The 1601 version of the text¹¹¹ provides the year of the finding, 1580 – but we are still left wondering as to the exact time of the year. Among the other passages of Pannonian Flora that refer to Batthyány estates and mention the year 1580, two passages also allow us to determine the month: Clusius collected „Tribulus aquaticus minor” that flowered in early June,¹¹² and „Liliasphodelus luteus” that flowered in late May, early June.¹¹³ The other Batthyány-related loci of the botanical work also show that he was there mostly in the late spring or the summer of any particular year. After all, Clusius found the fossil wood most probably in May or June, and we also know that he received Cromer's “first” letter on May 23, in Vienna. It cannot be decided which was earlier, but we have evidence that Clusius had the two experiences during the same time of the year.

We saw from Cromer's letter of May 1580 that the two men seem to have had previous discussions about the origin of such underground findings. What Clusius's stance may have been about the Zuckmantel findings we do not know, and in Pannonian flora, too, he just describes the specimen he found (in line with the descriptive nature of the work). At any rate, he speaks about the tree as something that once lived but then turned into stone.¹¹⁴ (The other aspect of origin, whether an underground specimen was born in situ or brought there by floods and so on, does not seem relevant here, since this was a surface finding.) After all, we can reinforce that Clusius had a conscious interest in what we today call palaeontology. In this respect the two cases fruitfully complete each other. The finding of the „Lithoxylon” was not an isolated, chance event: related issues had emerged in earlier scholarly conversions, and Cromer's reports gave further opportunities to think about questions of origin.

These concerns were not limited to ancient plants, but animal fossils came into the picture, too. Again, the scarcity of relevant surviving letters by Clusius himself does not allow us to learn his thoughts about “stones” with features of marine shells and other animals, but it cannot be accidental that several scholars sent him such specimens during his life, for instance, Giacomo Antonio Cortuso (1513–1603). Clusius corresponded with this eminent Italian scholar, who made long journeys in a number of countries and finally became the prefect of the Paduan botanical gardens,¹¹⁵ from the 1560s up to at least the 1590s, exchanging mainly botanical naturalia. In response to a letter by Clusius sent via Thomas Rhediger on March 1, 1567,¹¹⁶ some six months later Cortuso sent a box with “great¹¹⁷ petrified animals” (among other things), “which can be found amid huge and very hard rocks in our higher mountains near Padua and Vicenza.”¹¹⁸ What these animals were we learn, at least to some extent, from a later letter by Cortuso dated February 14, 1568: “If you like this sort of petrified shell and fish of which I sent a sample, just tell me to send more, as much as I can.”¹¹⁹ So, these were remnants of little marine animals – just the kind of fossils whose mysterious presence in high mountains launched debates in the sixteenth century about their origin, with the vis plastica of nature and diluvial floods as the two most dominant theories.¹²⁰ Clusius received both letters in March 1568 (the letter with a box attached to it took much more time to arrive from Padua to Mechelen than a single letter), and replied to both within days;¹²¹ – we can only wish we knew what. At any rate, Cortuso soon sent another box containing various items – he did not detail its contents in the brief accompanying letter which he apparently wrote in a hurry between two journeys.¹²²

Did Cortuso send the fossils of his own accord, or did Clusius encourage him to send any strange “stones” in addition to botanical naturalia, perhaps in the letter of March 1567 sent via Rehdiger? It was just in this period that Clusius expressed his enthusiasm for “stones” in letters to Crato (November 1566, March 1567), and requested aetites from Rehdiger (November 1566) and Saint Ladislaus's coins from Crato (March 1567). Furthermore, in a letter to Rehdiger we have not mentioned before, dated October 1, 1567, Clusius asks for such little stones (among other things) that display impressions of any (part of an) animal or the name of which comes from an animal, as in the case of aetites.¹²³ Rehdiger was already in Padua at this time and apparently met Cortuso whom Clusius greets in the letter in question. It seems that for some reason our Low Countries naturalist associated the Paduan or North Italian region with the possibility of acquiring animal-related stones; however, it was not Cortuso sending fossil shells and fish that gave Clusius the idea, since he did not receive these (or Cortuso's accompanying letter) until 1568. After all, it is quite possible that it was Clusius who had broached the issue of animal-like stones to Cortuso in his letter of March 1567 (or before), and that Cortuso's box was a reaction to such requests. It is remarkable that in his letter of October 1, 1567 to Rehdiger Clusius speaks of impressions of animals on stones and not about petrified animals, although, if anything, it was the latter type that appeared in mid-sixteenth-century review books on non-living naturalia.¹²⁴

As in the case of minerals, Clusius not only received, but also sent or mediated stones of a curious shape. By 1600, much more information and many more images were at the disposal of naturalists about what we today call fossils, thanks principally to Ferrante Imperato's and Johann Bauhin's above-mentioned works; and parallelly, the circulation of such specimens in the respublica litteraria also increased significantly. This is well reflected by a series of exchanges of fossils (among other things) between Italian and Low Countries naturalists in 1600, where the main axis and the main source of information was the correspondence between Pinelli and Clusius. From a letter by Pinelli dated January 6, 1600 we learn that Imperato – the owner of one of the greatest collections of non-living naturalia – needed Astroites and turned to Pinelli (also Neapolitan by origin) who in turn asked Clusius, since he, that is Pinelli, had heard that this kind of stone could be easily procured from England.¹²⁵ Pinelli refers to Bauhin's treatise De lapidibus variis, even mentioning the page number where the description and image of this Astroites can be found (see our Fig. 5a) – these small stones are shaped like five-pointed stars and fit together. The “Astroites” or “Asterias”, already described by Gessner who in turn refers to Pliny,¹²⁶ must in reality be a fossil part of an ancient marine animal called Crinoid (“sea lily”).¹²⁷ Its “stalk”, by which it was attached to the sea bottom, was made up of calcareous plates, and these star-shaped plates fell apart after its death, so the fossil parts can be found mostly distinctly but close to each other (see Fig. 5b).

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a. “Astroites” in Bauhin (1598, Section De lapidibus variis…, 31). b. Fossil remnants of a crinoid

Citation: Hungarian Studies 37, S; 10.1556/044.2023.00243

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Clusius answered to Pinelli in the positive in his letter of February 11;¹²⁸ Pinelli thanked him in his letter of March 16 for having “commissioned” the Astroites to be sent from England.¹²⁹ From Pinelli's letter of May 4 it turns out that Bernardus Paludanus (from Enkhuizen) offered Astroites, together with two further presents, lapis trochites and cornu Ammonis.¹³⁰ “Trochites” is “wheel-like” stone, described for instance by Gessner,¹³¹ while the “Horn of Ammon” is a “stone” known from antiquity but only identified in modern times. It is in fact the shell of an ammonite (ammonites), a type of cephalopod, similar to a snail's house.¹³² Gessner provides one schematic illustration of the “Horn of Ammon”,¹³³ while Bauhin shows a host of images about its various types (one can be seen as Fig. 6).¹³⁴ Imperato was very glad about the three “stones” and wanted to know where Paludanus had acquired them from; for Clusius he offered a copy of his Dell'historia naturale that had appeared in the previous year, and which focuses on non-living naturalia, complete with a host of illustrations.¹³⁵ (The book indeed arrived to Clusius later.¹³⁶) All in all, we can witness here a fairly neat chain of exchanges involving four leading scholars of the period: we may trace the way in which three different fossils journeyed through the stations of Paludanus (Enkhuizen) – Clusius (Leiden) – Pinelli (Padua) – Imperato (Naples) in a relatively short time. We can also learn from the correspondence that it was once again natural historical works, most importantly Bauhin's, that had apparently triggered the chain of transactions. In the case of Astroites, Bauhin's work is explicitly referred to, and on the „Horn of Ammon” it is Bauhin again who provides the most abundant visual material. These stones are beautiful, but the scholars would have probably been even more intrigued if they had known their real origin: in at least two cases it could be established that these were remnants of marine animals, whose presence on land (even in mountains) puzzled contemporary naturalists.

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An “Ammonites” in Bauhin (1598, Section De lapidibus variis…, 16)

Citation: Hungarian Studies 37, S; 10.1556/044.2023.00243

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Still in 1600, some further “stones” travelled from Clusius to Pinelli. Small pieces of “pea-like” stones, “piselli pietrificati”, probably from the same dripstone specimen that Clusius had received a generation earlier (see the beginning of this section), were sent not only to Pinelli, but several friends in Italy, certainly including Imperato and Giovanni Pona.¹³⁷ What is more, Astroites finally also arrived from England, thanks to Clusius's previously mentioned mediation in his letter of February 11 (see above). According to intriguing letters between Clusius and Pinelli that cannot be analysed here for reasons of space, Mathias de l’Obel (Lobelius), Clusius's friend and colleague, managed to acquire Astroites in London from the physician Thomas Doyle, who had collected them at Lassington near Gloucester. Clusius received them in early August and forwarded them, together with other items, on August 31; Pinelli received all of these despatches by October 24.¹³⁸

The most specific description of fossils in Clusius's correspondence known so far occurs in a letter by Nicolas Fabri de Peiresc (1580–1637). This French nobleman was two generations younger than Clusius, but had similarly wide-ranging humanist–naturalist interests and a similar ambition to build a Europe-wide network.¹³⁹ His enthusiasm for nature and his natural historical skills are easy to recognise in his letter to Clusius dated Aix-en-Provence, February 15, 1605, which Hunger had already noted,¹⁴⁰ and which includes a description of a mushroom (Clathrus Cacellatus Fr.) that Florike Egmond and other modern scholars highlighted as an exemplary description from a scientific perspective.¹⁴¹ Let us now turn to a previously undiscussed passage about fossils sent to Clusius: in the box that contained specific naturalia from the Marseilles region Peiresc included four kinds of fossil „stones” accompanied by a twelve-line description of the findings in the letter;¹⁴² he also enumerated them (in a somewhat different order) in the inventory attached to the letter.

1. –The first item is “pieces of our stone Astrites”, which has branches similar to red corals, but it is grey, and dotted with small “stars”. They can be found near Le Castellet, where Peiresc saw a branch not unlike white coral. (See part [1] of the quotation in the footnote. The item is specified in the inventory as Astrites, ejusque in formam plantae nascentis ramuli.) This is not the Astroites or Asterias seen above – here the name indicates the small stellar figures on the coral-like object; however, corals with this name do not feature either in Gessner or in other standard works on natural history. Imperato does specify in his 1599 work a corallo stellato (with corallo rosso, nero, bianco, articolato as the other coral species¹⁴³), but Peiresc does not seem to have been familiar with this, otherwise he would have referred to it (in the letter he only refers to red and white corals). Peiresc's Astrites must be identified with the fossil version of Imperato's corallo stellato, which in turn must be identified – based on Imperato's illustration (Fig. 7) – with today's Alcyionidae from the order of corals (Alcyonacea). As regards various species of Alcyionidae, the corallo stellato is quite similar for instance to “Dead man's fingers” (Alcyonium acaule or Alcyonium palmatum).¹⁴⁴ The “stars” are in fact traces of the small polyps that exhibit radial symmetry, and cover the skeleton of a living coral. It is the skeleton of certain corals that resemble bushes or branches, but corals are in fact animals – colonies of little polyps, and not plants.¹⁴⁵

   

   

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   Corallo stellato in Imperato (1599, 718)

   Citation: Hungarian Studies 37, S; 10.1556/044.2023.00243

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2. –Next come three specimens of petrified shells (Conchitae genera tria in the inventory). One of them is Lepadites, Lepas Alapede concha univalvis (the second item in the inventory passage; part [3] in the passage in the letter). According to Peiresc, it “may be the Trochites of Kentmann and Gessner”, but is totally similar to a limpet that attaches itself to rocks near Marseilles, called “Alapede”, therefore he would rather call it Lepadites (lepas means limpet). Based on the wheel-like pattern suggested under the name Trochites, the adjective univalvis above, and the information that it looks like a shell that attaches itself to rocks, the specimen can be identified as a fossil of a common limpet (Patella vulgata, see Fig. 8), which can be found on the rocky shores of Western Europe.

   

   

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   Common limpets ((Patella vulgata)

   Citation: Hungarian Studies 37, S; 10.1556/044.2023.00243

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3. –The Conchites vera striata (third item in the inventory passage, part [2] in the letter) indicated a fossil of a striped shell which according to Peiresc looked like a real concha striata; this type features in Kentmann and Gessner,¹⁴⁶ but is too general to identify with a specific species.
4. –Finally, the Ctenites Gesneri, striatus (fourth item in the inventory passage, part [4] in the letter) is again a striped shell that Peiresc acquired from the rocks of Antibes (also on the French Riviera) and “is perhaps the Ctenites of Gessner”. Both Gessner and Kentmann mention certain Ctenites, but their identity is again uncertain,¹⁴⁷ and Peiresc himself is not sure that his specimen is identical with that represented in Gessner (Fig. 9).

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A Ctenites in Gessner (1565, De rerum…, 164v)

Citation: Hungarian Studies 37, S; 10.1556/044.2023.00243

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It is conspicuous how cautious Peiresc is in his description when it comes to forming any theory as to the origin of these strange stones that definitely resemble certain known marine species. He does not even commit to writing the idea that they appear to be “petrified” living beings, he always speaks about a “similarity” to them, although he is clearly impressed by the high grade of similarity. The other striking feature of Peiresc's description is his adherence to Gessner. He intends by all means to fit his specimens into Gessner's categories, even when this results in forced associations of which he himself is not sure (“may be the Trochites of Kentmann and Gessner”; “perhaps Gessner's Ctenites”), while he could have found more types of corals in Imperato, and more types of shells in, say, Bauhin. This, at any rate, shows the great authority of the Swiss naturalist continuing Aeven after 1600.

The issue of strange stones or fossils appears several times in Clusius's correspondence: the above overview of examples stretched from the mid-1560s to the 1600s. As in the case of minerals, it was in his early period that he demonstrably looked for certain special “stones”, while he seems to have played more passive roles in such issues in his later years. After all, he must have had several of such naturalia by the end of his life; he may have given away some, but such items as “Saint Ladislaus's coins”, the fossil remnants of the oak that he himself found, or Pereisc's marine presents certainly formed part of the great number of “curiosities” indicated in the auction catalogue drawn up after Clusius's death.¹⁴⁸

The above examples are also telling from a more general perspective: they present us with a cross-section of the exchange of strange stones and fossils that took place in the late sixteenth-century Republic of Letters (not only in Western but also in East Central Europe), and complete the image we have seen in the relevant review works of the period by Gessner, Bauhin or Imperato. In our sample letters, animal fossils came from small marine animals, while plants were represented by fossil trees: in the natural historical works, too, these are the most frequently mentioned types for animal or plant fossils. Furthermore, there were stones – mentioned both in letters and review works – whose strange shape was due to other reasons than having been once living beings; and there were fossils that did not look like fossils at all, and thus completely misled contemporary scholars. In certain cases, even the best naturalists of the time could not help putting objects in totally different categories than what they really are. The question seemed to be whether a coral is a plant or not – but it is in fact a colony of marine animals. Or, has the “Saint Ladislaus's coin” something metallic, or is it just a strange shaped stone? Neither of them, but a petrified eukaryote. Such cases may make one smile, but what really counts is the enthusiasm and activity of the scholars of Clusius's time, which accelerated scientific development and thus paved the way for exact identifications many generations later. Clusius himself took part in the birth of palaeontology: he acquired or circulated several fossils, and even found some himself.

Due to the practical orientation of correspondence in Clusius's time, we rarely get to read explicit ideas or theories about the “stones” in the letters themselves – instead they tend to contain references to sending or receiving such objects, or short descriptions. We have an important exception – Cromer's report about the discussion between himself and the miners,¹⁴⁹ but here, too, the author refers to earlier discussions with Clusius for which we have no source. Still, the way the scholars speak about the objects (for instance, whether they refer to petrifaction or not) or the categories they use can be informative with respect to „palaeontological” ideas of the time. The real significance of the passages quoted from these letters, however, lies in the fact that they provide living examples of how scholars used to search for, collect or forward such objects – in other words, how the subject matter of these review works about lapides was actually handled. We can see the naturalia not in a scientific but in a biographical or micro-historical context, and may come to understand, for instance, what kind of factors contributed to their increasing circulation; we get to appreciate how individual travels and adventures (like that of Cromer in the mine) and the increasingly dense network of the European respublica litteraria (with Clusius's network stretching from England to Silesia or Transylvania) were among the most important factors. We can see how the information contained in, say, Gessner's of Bauhin's work triggered real activity, and how, in turn, this activity resulted in more knowledge, more detailed and illustrated works on natural history. The fact that our last sample letters, those from the 1600s, report sending multiple objects, and testify to chains of exchanges with several stations, is in line with the spectacular development in the scholarship of “stones” from Agricola to Bauhin or Imperato (seen already in the sheer volume of descriptions and illustrations of fossils). Speaking about reception of the lapides-literature, Gessner's influence has to be underlined once again: several of our sample letters reinforced the influence of the 1565 edition of De omni rerum fossilium genere, particularly the last treatise, by Gessner himself.

6 Special types of earth

“Earths” was one of the general types of fossilia or res metallica in the classificatory system of most review works on non-living naturalia. Being less spectacular than minerals or fossils, perhaps we would not expect such materials to have been objects of investigation and exchange between scholars – but they were, as Clusius's correspondence shows. It was already shown that Achilles Cromer was intrigued by solea, a constituent of a geological layer in the Zuckmantel mine, a special earth which, according to him, “endeavoured upwards”, and a sample of which he sent to Clusius.¹⁵⁰ This is an example of purely scientific interest on the part of these scholar(s). All of our other examples for the exchange of earths are to be discussed in the context of terra sigillata, medicinal earth or bole (bolus in Latin; in fact the term was used to refer to various types of clay). As will be seen from the next paragraph, terra sigillata was principally a medicine used mostly in the form of tablets and, strictly speaking, the exchange of medicines should not belong to the scope of this study. However, since medicinal earths also appeared in curiosity cabinets and collections of naturalia, and could also be objects of scientific interest, relevant examples from the correspondence will be reviewed in this section, albeit in somewhat less detail than the previous sections.

Terra sigillata is a special type of clay used for medicinal purposes since antiquity: it was a famous antidote for poison, but its various types were also in demand as a remedy for plague, as an adstringent or absorbent.¹⁵¹ Its most renowned variant was produced in Lemnos (terra Lemnia), but other Aegean localities (Chios, Samos and so on) also provided medicinal earth, as some regions more to the east (terra Armenia being the most important “oriental” type). It was mostly¹⁵² cut into a round tablet form (troche or pastille), marked with a seal using a special device for authentication, and traded in this form, hence the name terra sigillata. After conquering the Aegean region, the Ottoman Empire monopolised the production of this clay. New, Turkish devices appeared on terra Lemnia, and it served, among other things, as a present of the sultan given to, notable individuals such as Western ambassadors. The situation in the East prompted the exploration of new finding places for medicinal earths, and in the second half of the sixteenth century new types of terra sigillata were discovered and produced at various localities in Europe. Two of these variants coming from East Central Europe occur in our sample letters: “Silesian earth” and “Tokaj earth”. Parallelly with the growing popularity of medicinal earths in the period, scholars described more and more earth types in natural historical reviews or medical treatises. By this time, the names of certain types were transferred, based on the similarity of properties, to earths produced in other regions – for instance, “Armenian bole” as a general term could denote earths from various localities of Europe in the terminology of, say, Matthioli or Aldrovandi. Thus it was/is not always easy to establish the real place of origin behind the geographical name, not to mention counterfeited specimens whose circulation also grew in the period.¹⁵³ Terrae sigillatae also showed up in collections of naturalia like that of Matthioli, Aldrovandi or Imperato. In this case, the earths were clearly not collected for principally medical purposes - instead it brought great prestige to own a great variety of such troches, each type marked with its own device, similarly to the possession of numismatical collections.¹⁵⁴ Illustrations based on scholars' collections in Early Modern works on natural history are our most important sources as to the physical appearance of these objects, since the material itself has not survived. Medicinal earth was also exchanged in crude form, but no illustration of such specimens seems to have survived.

Among the several works on natural history and medicine that Clusius translated into Latin, two contained information about terra sigillata: Antidotarium (1561)¹⁵⁵ and, more importantly, Belon's Observationes,¹⁵⁶ the original of which was one of the first reports in Western Europe about the production of terra Lemnia.¹⁵⁷ These are translated passages from the works of other scholars. What indicates that Clusius was truly involved with medicinal earths is the description of his collection in the 1609 auction catalogue, according to which he owned, among other things, supellex… mineralium… complurium, terrarum sigillatarum, et permulta alia similis curiositatis.¹⁵⁸ The fact that beyond sets of “minerals” and many “other similar curiosities”, terrae sigillatae is specified as a distinct category, suggests that there must have been several specimens or portions in evidence. These items were not necessarily the usual troches, with a “seal” on them: by the late sixteenth century terra sigillata had come to denote medicinal earth in general, in any form.¹⁵⁹ What kinds of terrae sigillatae did he exchange, and with whom? Was Clusius scientifically interested in this naturalium?

In the time when Clusius corresponded with Crato about the Saint Ladislaus's coin, Crato also sent a certain terra Caffensis, on October 16, 1567.¹⁶⁰ This type of earth probably originated from Caffa (today Feodosia) in Crimea, which belonged at the time to the Ottoman empire.¹⁶¹ We have Clusius's response dated Bruge, November 25, according to which he received the earth wrapped in paper, “but almost reduced to powder” by foreign hands that had investigated it.¹⁶² These words suggest that it may have been originally a troche. At any rate, Clusius was happy to receive the specimen and encouraged his friend to send similar items if he could, “since you would not believe how zealous [or “fond of”: studiosus] I have always been about all things exotic;¹⁶³ so it is little wonder that I eagerly look forward to receiving the little stones [the Saint Ladislaus's coins] and the other things you promised.”

In early 1583, Joachim Camerarius Jr. published a book of treatises about the plague and its treatment, including a treatise he himself had authored about Armenian and Lemnian earths.¹⁶⁴ When in his letter of April 9 Clusius replied to Camerarius, thanking the latter for the copy sent to him, it was this treatise about medicinal earths that he specifically mentioned as one he had “read with pleasure”. But since Clusius was not persuaded that Camerarius's knowledge regarding the Armenian bole was exhaustive, he sent to his Nuremberg friend various earth types: (1) a fragment of crude Armenian earth (rudis fragmentum…); (2) a kind of crude Lemnian earth; (3) two troches (pastillos…) of “more pure” Lemnian earth; (4) a further troche of fine (lota¹⁶⁵) Lemnian earth; (5) and a crude fragment of an “oriental red bole”.¹⁶⁶ Enumerating these items, Clusius adds to each that he had received them from Ogier Ghiselin de Busbecq. Busbecq stayed in the Ottoman Empire (mostly as ambassador of the Habsburg emperor) from 1554 to 1562, and his role in mediating oriental cultural goods to the West is well known. Clusius, who followed Busbecq in the position of quasi botanist to the emperor, was on good terms with his compatriot. They corresponded and even met several times in Vienna, and it was probably on one or more of these occasions (between 1574 and 1582) that Busbecq presented his friend with the terrae sigillatae. Clusius notes that in order to acquire the crude Lemnian earth, Busbecq sent his physician, Willem Quackelbeen, to the island of Lemnos itself. This and the repeated mention of Busbecq, who was a trustworthy friend and famous man of letters, reinforced the authenticity of the material. The fact that Busbecq gave Clusius such earth is not surprising in itself: it was a usual present of the sultan to ambassadors,¹⁶⁷ and the Flemish man of letters forwarded specimens and/or information about them to several of his acquaintances.¹⁶⁸ More surprising is the variety of the specimens: Busbecq provided a kind of cross-section of the main types of terra sigillata produced in the Turkish Empire, including earths in their original, crude form. The scientific interests on part of both Camerarius and Clusius are clear.

By this time, Clusius certainly possessed medicinal earths from other, more western parts of Europe. According to Cromer's second letter of 1580 examined in Section 3, the Silesian physician saw in the Zuckmantel area “red earth that could have the effects of Armenian bole, which it seems to imitate. You will receive this partly in crude and partly in fine and prepared form.”¹⁶⁹ It is highly interesting that Cromer not only alludes to finding a new type of medicinal earth perhaps as valuable as the Armenian type, but was also able to send a “fine and prepared” form of the substance, although this could hardly have been an official, stamped type of medicinal earth. The issue needs further research; here it suffices to say that various types of terra Silesiaca had been produced and traded by the 1580s, and Cromer was obviously keen on discovering such earth in the region of Neisse, his home town (south of Breslau). The first and foremost type of Silesian bole was discovered around 1550 in an abandoned goldmine near Schweidnitz (Świdnica), south of Striegau (Strzegom), by Johann Schulz (Montanus or Scultetus Trimontanus), a Paracelsian physician; due to its allegedly similar nature to gold, this terra sigillata Strigoniensis was also called Axungia solis, “sun grease”. Soon, other production centres emerged, like Liegnitz, Jauer and Goldberg (similarly to the west of Breslau), each type having its own sealing device. Terra Silesiaca enjoyed great publicity – from 1583 onwards distinct treatises were written on it in several languages.¹⁷⁰ No wonder that by 1593 Cromer was again sending “Silesian earth” to Clusius (who was already in the Low Countries), this time troches (rotulae), that is, official medicinal earth samples of any of the above mentioned types. Cromer believed them to make nice presents, tokens of his affection for his old friend.¹⁷¹ Perhaps terra sigillata and its Silesian types formed part of their scholarly discussions referred to in the letters; at any rate, in both 1580 and 1593 Cromer was sure – certainly not without reason – that Clusius was interested in the new types of earth.

Our Low Countries naturalist received bole from Tokaj, too, a town that gave its name to the famous wine region Hegyalja in the north eastern part of the Kingdom of Hungary. Terra Tokajensis was again a type increasingly demanded in the period; there is no space here to present it according to its significance, but it appeared in more contemporary treatises than noted so far in scholarly literature.¹⁷² This type of earth could be found principally in a mine of the Tokaji-hegy (Mount Tokaj) west of the town. Three brief references to this bole can be found in Clusius's correspondence with Claude Roussel, the Kassa-based captain general, then vice captain general of Upper Hungary¹⁷³ in the late 1580s,¹⁷⁴ whose person and relationship to Clusius is little known. In response to a letter by Clusius dated October 1, 1588 (by this time he had already arrived in Frankfurt from Vienna), Roussel assures the former on December 4 from Tokaj¹⁷⁵ that he would be able to procure terre de Thocchay when its season comes, and to send such via a certain “von Eck”, who can be none other than Christoph Freiherr von Eck.¹⁷⁶ On February 24, 1589 he repeats this promise.¹⁷⁷ Finally, on May 8, 1589, he reports, “these days I have sent a little vessel (un petit vasselle) of our Tokaj earth” via von Eck.¹⁷⁸ If the material was in a vessel, it could not be troche(s). It is certain that Clusius had requested it and not just received it as a present: in his first letter Roussel had used the phrase “the Tokaj earth that you request (demandez)”. Clusius did not necessarily have to read treatises to know of this Hungarian type of medicinal earth: it was used, for instance, against the plague in contemporary Vienna.¹⁷⁹

So far we have too little information to establish whether Clusius (or an acquaintance for whom he mediated) actually needed the terrae sigillatae for medical purposes; at any rate, it was advantageous to have such drugs, if for no other reason than because the plague continued to flare up from time to time in the period in question.¹⁸⁰ What is certain from the above examples is that the boles (also) intrigued Clusius as a naturalist, similarly to minerals and fossils. This can be seen from the crude versions among the received specimens, the way he reacted to Joachim Camerarius Jr.’s treatise, or from the correspondents' allusions to how Clusius would value their gifts. By the 1590s Clusius must have owned a variety of terrae sigillatae; while large-scale collecting is not probable, he was certainly glad to have access to as many types (and forms) as possible.

7 Conclusions

The above investigations (Parts I and II) were intended to contribute to our knowledge regarding, on the one hand, Clusius and his network, and on the other, various – mostly practical – aspects of contemporary natural science. To begin with Clusius himself, it is now certain that non-living naturalia formed an integral part of his world all through his life, and in at least one period – in the early phase of his active scholarly career – he was demonstrably enthusiastic about them. Let us remember how he yearned for aetites, Saint Ladislaus's coin or res metallica in general in 1566–67, or how Cromer spoke to him, sending a great variety of underground naturalia and referring to earlier discussions. For the later years it is difficult to establish his attitude (due, among other things, to the lack of surviving letters on Clusius's part of the relevant strands of correspondence); at any rate, the number of specimens he received in his old age was not diminished compared to the 1560s–70s – sometimes he himself would send something, at others he would mediate between other members of the Republic of Letters. His enthusiasm, however, must have diminished at least to some extent. We have found almost no certain reference to direct request of such naturalia from this later period, even in his correspondence with some key collectors such as Aldrovandi; on occasson he would even give away some specimens he had received before (“pisolithum” and a piece of silver ore); and eventually he refrained from lecturing on res metallica in Leiden, although this may have had reasons other than lack of interest. Still, it can be no accident that whenever his correspondents broached the issue of a certain non-living naturalium, they would as a rule, take it for granted that Clusius was interested in matters of the kind. The bare fact that even after a partial review of his surviving correspondence more than 50 letters have been found with such naturalia among the topics (plus a few passages in his printed works¹⁸¹) speaks for itself.

These results reinforce what is already known but still not emphasised enough in scholarship: botany was only one of Clusius's fields of concern, and he was open to all miracles of nature. While in our terms Clusius was principally a botanist, his contemporaries seem to have regarded him rather as a naturalist or man of letters whose main field was botany, but who had several other skills and interests. Non-living naturalia were one of these, and this also means that he was more closely connected to the world of „museums” or “Wunderkammer” than has been believed previously. To be sure, to speak about Clusius as “naturalist” is also a crude oversimplification, given his many typical humanist concerns (epigraphy, editing the works of other humanist authors and so on), which are again relatively neglected in scholarship.

The Middle Ages was mostly interested in the medical uses of what we call non-living naturalia – let us consider for instance the lapidaria –, and in the sixteenth century they were still presented in a medical framework in university curricula (similarly to plants), at least on the institutional level. A number of the specimens appearing in Clusius's correspondence had widely known healing properties (“virtues”), or were raw materials for drugs; he himself was a trained physician. All the more conspicuous is the fact that no reference is made to the medical use of the despatch in any of our examples, not even in the case of terrae sigillatae. It cannot be ruled out that specimens that were considered to have (direct or indirect) healing properties were indeed required and used for such purposes in Clusius's circles, but, in the letters at least, they do not appear in their medical, but in their “scientific” context (in the sixteenth-century sense) as “wonders of nature”, as objects of investigation and as collectibles. The examples from the correspondence illustrate clearly the paradigm shift that took place in the course of the sixteenth century and that led to the birth of mineralogy, geology and so on, as distinct sciences. At the same time, we are still at the beginning of specialisation in the period in question, and it is precisely this fresh look at objects as wonders of nature, their unstable classification and their curiosity for the observer that add a special charm to this period of Renassiance scholarship. All in all, the frequency of such objects and the way they were spoken about in Clusius's circles are in line with what modern literature revealed about the new attitude to nature and the significance of museum type collections in the sixteenth century.

Naturally, Clusius focused on plants, seeds and gardens, and did not build an extensive, representative natural historical collection à la Imperato or Paludanus. Still, similarly to many other members of the late sixteenth and early seventeenth-century Republic of Letters, in the end he did have a considerable collection, with several non-botanical categories of objects that appeared in the exemplary museums of Italy or the Low Countries (minerals, terrae sigillatae, coins and so on) and with several items within each category. This can be seen clearly both from the passage of the auction catalogue we analysed, and from the sample letters. Variety is a characteristic trait of collections, and indeed, based on the letter examples there must have been various specimens within each groups of non-living naturalia in Clusius's collection: metallic ores, crystals, non-metallic minerals like vitriol; fossilised marine animals, fossilised tree fragments and various other curious “stones” (not necessarily fossils), as well as both Oriential and western types of medicinal earths, in both crude and prepared forms.

Clusius's network extended to almost all parts of Christian Europe; therefore, beyond the interests of Cluisus himself the sample letters seem to provide a good cross-section of the exchange of non-living naturalia that existed in late sixteenth-century Europe in general. The scientific significance of descriptions or objects exchanged in the framework of humanist-naturalist correspondence has only been pointed out in the last decades of modern scholarship,¹⁸² and even today, the exchange of res metallica or fossilia seems to have been little investigated. The exchange of minerals and fossils, at least, must have been more frequent in the correspondence of the period than has been revealed so far, otherwise the great collections and great natural historical review books (with illustrations) could not have been born. Our sample letters reflect clearly the general principles of humanist-naturalist correspondence and exchange, most importantly that the exchange was not based on the rules of commerce but on the humanist notion of friendship, amicitia. True members of the respublica litteraria respected and trusted each other, they sent presents, did favours and were confident that in the long run they would benefit from favours; their amicitia and liberalitas did not allow the involvement of money. As we saw from Clusius's correspondence, these frameworks could even allow the sending of valuable metallic minerals, fragments of gold or silver for instance.

Scientific literature flourished in the second half of the sixteenth century: an increasing number of works reviewing res metallica or fossilia were written, as well as distinct treatises on “metals”, “stones” or “sealed earths”. Information about all of these found in letters neatly complete the picture about the development of science as seen from the theoretical treatises. Practical issues were dominant in the correspondence of the period, and the interesting theoretical debates – for instance about the origin of what we today call fossils – are seldom present in the letters. However, the passages from the letters can vividly attest to their authors' interest in non-living naturalia: these are real-life, real-time examples of how the contemporaries looked at the specimens, how they felt about them and what they did with them. Sometimes scientific literature and life events, such as the personal experience described in the letters may be linked directly: we saw how disputes about the origin of metals or fossils influenced Cromer in his choice of where he went and what he sent, or how Clusius reacted to the copy of Joachim Camerarius's book sent to him by sending in return a variety of medicinal earths. In general, letters can reveal a great deal about the reception of works on natural history in the Republic of Letters: our examples included several references to Agricola, Gessner or Bauhin (sometimes even the page numbers in the books). With respect to “stones”, the most frequently mentioned reference work in Clusius's circles seems to have been Gessner's 1565 edition De omni rerum fossilium… genere.

It is worth looking at the spatial distribution of the places of origin of the specimens mentioned in the sample letters and of the places where they were sent from: the relevant map (Fig. 10) indicate only instances where we may be sure that the transaction was successfully concluded. In the case of minerals, these localities are concentrated in Saxony, and to a lesser extent in Southern Silesia (due to Cromer's adventures). As we have already discussed, Saxony became the centre of Montanwissenschaften, thanks principally to Agricola, and the richness of the region in such resources must have been one of the reasons why Clusius turned to men of letters in this country and extended his network in this direction. In the case of strange stones and earths, too, Central Europe, particularly East Central Europe, features heavily. Unsurprisingly, the objects mostly originate from the mountains (the places of origin are at various distances from the places of sending), more precisely from mines (like Annaberg, Zuckmantel or, probably, Tokaj) or from the surface (like the fragment of fossilised tree from Vas-hegy). Although the spatial distribution illustrated by the map is not fully representative, since it is based on a partial overview of a huge correspondence, still, it underlines the significance of Saxony and East Central Europe in Clusius scholarship – regions which have been relatively neglected compared to Western and Southern Europe. Saxony and Silesia seem to be almost white spots in the literature on Clusius, but in the case of many other countries, too, only a small part of his network has been examined. The above investigations have thrown some light on several little known relationships that Clusius held with significant men of letters of his age, particularly in Central Europe (like Achilles Cromer or Ludwig Camerarius). However, all of these correspondences were only explored from the perspective of non-living naturalia; a more general investigation of these sections of Clusius's world will hopefully be accomplished by future scholarship. In general, the great number and broad spatial distribution of the exchanges referred to in the sample letters we examined reinforce that Clusius was one of the key figures of the Republic of letters of the period, and also played a vital role as mediator between the western, the central and the eastern parts of Europe.

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Citation: Hungarian Studies 37, S; 10.1556/044.2023.00243

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