Henry IV's penance at Canossa

January 28, 1077

Stripped to a hair shirt in the Apennine snow, the excommunicated German king stood before the walls of Matilda of Tuscany's mountain castle for three days before Gregory VII agreed to see him. The pope absolved him. Going to Canossa became European shorthand for abject humiliation by church authority. Whether the penance was genuine contrition or cynical political theater has been debated by historians ever since.