Gregory VII
c.1020 - 10850
Pope
Gregory, known as Hildebrand before he became pope, was the most eminent medieval pope. He asserted his supremacy with the demand that the pope had the right to depose an emperor if the monarch was immoral.

He excommunicated the emperor Henry IV forcing him to travel to Canossa in Italy to plead for absolution.

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Biography

The Medieval Sourcebook:
First Banning of Henry IV, 1076

The Gregorian Calendar