Peter of Spain

Peter of Spain or, in Latin, Petrus Hispanus (13th century) is the Mediaeval author of Tractatus, a standard textbook on logic, and often credited with a number of works on medicine. He also wrote Summule logicales magistri Petri Hispani (Collection of Logic Matters of Master Peter of Spain) which has a large volume of manuscripts and printed editions. This is a strong indication his work enjoyed great success throughout European universities well into the seventeenth century.

Peter's true identity remains unknown. The word Hispanus refers to Hispania, often translated as Spain, but including the whole Iberian Peninsula (as a country, Spain exists since the late 15th century). It is often assumed he was Pedro Julião (ca. 1215-1277), the Portuguese physician known as Petrus Hispanus who in 1276 became Pope John XXI. Another theory asserted the author of the Tractatus was Castilian, and a member of the Dominican Order. Other theories from the fifteenth century point to Petrus Ferrandi Hispanus (d. between 1254 and 1259), or to a Blackfriar (Dominican) from the late thirteenth or early fourteenth century.