Peter of Spain (; Portuguese and ; century) was the author of the , later known as the , an important medieval university textbook on Aristotelian logic. As the Latin Hispania was considered to include the entire Iberian peninsula, he is traditionally and usually identified with the Portuguese scholar and ecclesiastic Peter Juliani, who was elected Pope John XXI in 1276. The identification is sometimes disputed, usually by Spanish authors, who claim the author of the was a Castilian Blackfriar. He is also sometimes identified as Petrus Ferrandi Hispanus ( 1254  1259).