Some of the manuscripts and books of the Hungarian humanist, Johannes Sambucus (1531–1584) are still kept in Vienna, in the Austrian National Library. A source of information puts a new light on the sale and reception of his library. In his last will made in 1583, Sambucus left his library, the manuscripts he still owned and his maps to his son, in 1584, not long after his death, his widow started negotiations about selling them to the Emperor Rudolf II. However, the data clearly suggest that Sambucus’ library did not become en bloc part of the Imperial Library, if the purchase took place at all: only 44 years after Sambucus’ death was a certain part of his library bought by Sebastian Tengnagel for both the Imperial Library and himself. Another result of the research confirms that the philologist Sambucus cannot be separated from the book and manuscript collector Sambucus, and the examples presented here justify why it is worth involving in the research the extant books of the Hungarian humanist.