One of the most popular medical books of the Middle Ages; first written about 1260. After its first printing about 1492 it was reprinted many times in the next 100 years. "Petrus Hispanus was the only practicing physician ever to become Pope (1276-77). By all accounts he was an interim choice when rival French and Italian Cardinals could not elect one of their own nationality. Although not clearly responsible for any major political actions by the Church, Petrus was famous for several centuries after his death because of his secular writings - a text on logic (Summulae logicales) and a handbook on medicine (Thesaurus pauperum). The latter is noteworthy because it contains two sections on coitus - how to enhance the sexual act and how to subdue sexual urges. Promoting coitus seems an odd topic for a medieval Catholic cleric-writer and raises the question as to whether the first section may have been added by a later copyist or editor, but an examination of a very early manuscript of the Thesaurus gives assurance that the two sexual sections were written by Petrus, probably around 1270." (https://www.ncbi.nlm.nih.gov/pubmed/24585747). ISTC no. ij00242000. Digital facsimile from Biblioteca Corsiniana, Roma (BEIC) at this link.