Pope Gregory VII

Born Hildebrand of Sovana around 1015, he spent years maneuvering behind the scenes before becoming pope on 22 April 1073. He launched the Gregorian Reform: mandatory celibacy for priests, a crackdown on simony, and a new canon law that put papal elections in the hands of cardinals alone. The collision came with Emperor Henry IV over who held the right to appoint bishops - the Investiture Controversy. Gregory excommunicated Henry three times; Henry responded by installing Antipope Clement III. Gregory died in exile on 25 May 1085, denounced by enemies as autocratic and cruel, later venerated as a saint. Centuries on, he remains the template for papal supremacy - championed and reviled in equal measure.