Pope Callixtus III, born Alonso de Borja, but referred to in English-language accounts as Alfonso de Borgia as a member of the House of Borgia, was head of the Catholic Church and ruler of the Papal S

Clement VIII, born Gil Sánchez Muñoz y Carbón, was one of the antipopes of the Avignon obedience, reigning from 10 June 1423 to 26 July 1429. When King Alfonso V of Aragon reached an agreement with Po