Pope John XXI

John XXI, né Petrus Juliani ( 1215 - May 20, 1277), a Portuguese named Pedro Hispano, was pope from 1276 until his death on May 20, 1277.

Note that the previous pope named John was Pope John XIX and there is no Pope John XX (see article for explanation)

He started his studies on the episcopal school of Lisbon cathedral, and later entered Paris university (although some historians claim that he entered Montpellier university instead), where he studied medicin and teology, with special enphasis to Aristotle's dialetic, logic and mainly physics and metaphysics.

From 1245 to 1250 he teached medicin at the Siena university, where we wrote Summulae Logicales which was the reference manual on aristotelic logics in use on european universities for more than 300 years.

After the death of Pope Adrian V, on August 18, 1276, Pedro Hispano was elected Pope at the conclave of cardinals on September 13, being crowned a week later. He died on May 20, 1277, after being seriously hurt in a Viterbo's Cathedral accident, which was on recovery works: a piece of the ceiling fell in his head. There lays his tomb. In May, 2000, a special and honorific tomb place was chosen, in the same temple.