ALL SAINTS CELEBRATED IN MAY Saints celebrated on the 20th of May WELCOME! JOHN XXI. (XX.), POPE ⬅️ Saintly Popes - Index He was born at Lisbon between 1210 and 1220; enthroned, 1276; he died at Viterbo, May 20, 1277. The son of one Julianus, he was baptised Peter, and was known as Petrus Juliani or Petrus Hispanus. After his earlier studies in the cathedral school at Lisbon, he entered the University of Paris and attended lectures on dialectics, logic, and, more particularly, those on Aristotelean physics and metaphysics then being given by Albertus Magnus. The natural philosophy of Aristotle had a special attraction for Peter. He zealously pursued the study of medicine, and also that of theology, attaching himself especially to the Minorite magister, John of Parma. On completing his studies, he was called in 1247 as professor of medicine to the University of Siena, which was at that time being greatly enlarged. Here he wrote his "Summulæ logicales", for almost...