Head of the Catholic Church from 1492 to 1503
Source (Wikipedia): Pope Alexander VI

Pope Alexander VI was head of the Catholic Church and ruler of the Papal States from 11 August 1492 until his death in 1503. Born into the prominent Borgia family in Xàtiva in the Kingdom of Valencia under the Crown of Aragon, Spain, Rodrigo studied law at the University of Bologna. He was ordained deacon and made a cardinal in 1456 after the election of his uncle as Pope Callixtus III, and a year later he became vice-chancellor of the Catholic Church. He proceeded to serve in the Curia under the next four popes, acquiring significant influence and wealth in the process. In 1492, Rodrigo was elected pope, taking the name Alexander VI.