In the 15th and 16th centuries, humanist scholars traced back the contemporary names of peoples and settlements to similar sounding ancient personal and geographical names. This is how they tried to establish a connection between antiquity and their own times. The same method was used by the Viennese Humanist Johannes Cuspinianus in his work Diarium, which is a report on the events of the 1515 Viennese Congress. Based on folk etymology, Cuspinianus traced back the Latin names of four Hungarian towns (Suppronium, Posonium, Iaurinum, Strigonium) to ancient roots. The analysis of the text suggests that in the case of three towns out of the four, the author made use of Antonio Bonfini’s RerumUngaricum decades as a source. As for the remaining town, he followed in the footsteps of earlier humanists and developed his own etymology. The Bonfini-based discussion of the etymologies of the three names can also be found in Austria, another work written by Cuspinianus around 1528. This seems to refute the idea commonly adapted in the literature that Bonfini’s work was completely ignored by scientific circles between the mid-1510s and the 1540s. In light of the above, it may be well worth researching the works of contemporaneous humanists for further traces of the Decades.