First printed in 1593, Antonio Possevino's comprehensive Bibliotheca Selecta included a series of lists of books which Jesuit college and seminary libraries should own. Before this was published, though, a number of Jesuit colleges opened in southern Europe, and housed relatively large libraries. The colleges in Siena and Florence contain large inventories of books dating from 1565 and 1578, but no instructions on collection and few on maintenance. Very little information remains on how these libraries were created, yet comparing the collections with the later work, which describes an ideal gathering of books, is instructive and can shed light on such issues as which authors and what subjects were considered required reading for Jesuits. There is no evidence that the existing libraries were influential in Possevino's development of what amounts to an Index of Recommended Books.