Pope Callixtus III (, , ; 31 December 1378 – 6 August 1458), born Alfonso de Borgia (), was head of the Catholic Church and ruler of the Papal States from 8 April 1455 to his death in August 1458. Borgia spent his early career as a professor of law at the University of Lleida; he later served as a diplomat for the kings of Aragon. He became a tutor for King Alfonso V's illegitimate son Ferdinand. After arranging a reconciliation between Alfonso and Pope Martin V, Borgia was made Bishop of Valencia. In 1444, Pope Eugene IV named him a cardinal, and Borgia became a member of the Roman Curia. During the siege of Belgrade (1456), Callixtus initiated the custom that bells be rung at midday to remind the faithful to pray for the crusaders. The tradition of the Angelus noon bell still exists in most Catholic Churches to this day. He was also responsible for the retrial of Joan of Arc that saw her vindicated. He appointed two nephews as cardinals, one of whom became Pope Alexander VI. He is the last pope to date to take on the pontifical name "Callixtus". Family Alfonso de Borgia was born in La Torreta in 1378. La Torreta was at the time in the Señorío de Torre de Canals (but is now a neighborhood of Novele in Jativa). At the time he was born in the Kingdom of Valencia under the Crown of Aragon. He was the eldest child of Juan Domingo de Borja y Doncel and Francina Llançol. His sister Isabel married Jofré Llançol i Escrivà (son of Rodrigo Gil de Borja y Fennolet), and become the mother of Pedro Luis de Borja and Pope Alexander VI. His other sister Catalina became of the mother of Luis de Milà y de Borja. Alfonso was baptized at Saint Mary's Basilica in Xativa, where he is honored with a statue in his memory. Early church career Borgia studied grammar, logic and the arts in Valencia and went in 1392 to the University of Lleida where he obtained a doctorate in both canon law and civil law. His early career was spent as a professor of law at the University of Lleida. Around 1411, he attended a sermon by Vincent Ferrer. Afterward, the Dominican said to the future pope: "My son, you one day will be called to be the ornament of your