Peter of Spain is the author of Tractatus, a famous work on logic which was probably written between 1230 and 1245. Later this became known as Summulae logicales magistri Petri Hispani (Logical matters of Master Peter of Spain).The quantity of manuscripts and printed editions existing indicate that it was widely studied in European Universities right until the 17th century. He is also reputed to have written a number of works on medicine. The best known of these is Thesaurus Pauperum. Peter's true identity remains unknown. He is thought to have written his famous works in Northern Spain or Southern France in the 13th Century. Taken from a 14th century fresco.