Pope John XXI - Pre-papal Life

Pre-papal Life

Pedro Julião was probably born in Lisbon between 1210 and 1220. He started his studies at the episcopal school of Lisbon Cathedral and later joined the University of Paris, although some historians claim that he was educated at Montpellier. Wherever he studied, he concentrated on medicine, theology, logic, physics, metaphysics and Aristotle's dialectic.

There are some who believe he must be identified with an individual known as Peter of Spain. On the basis of this premise, he is the person who from 1245 to 1250 became known as Pedro Hispano (because he came from Hispania, the Iberian Peninsula), and taught medicine at the University of Siena. There, he wrote the Summulae Logicales, a reference manual on Aristotelian logic that remained in use in European universities for more than 300 years. He became famous as a university teacher, then returned to Lisbon. At the court of Guimarães he was the councilor and spokesman for King Afonso III of Portugal in church matters. Later, he became prior of Guimarães. He tried to become Bishop of Lisbon, but he was defeated. Instead, he became the master of the school of Lisbon. A notable philosopher with works in logic, he was also the responsible for the creation of the Square of opposition.

Pedro became the physician of Pope Gregory X (1271–76) early in his reign. In March 1273 he was elected Archbishop of Braga, but did not assume that post because on 3 June 1273 Gregory X created him Cardinal-Bishop of Frascati.