Matilda of Canossa and the Walk to Canossa

In a dispute over who could appoint bishops, Pope Gregory VII excommunicated the German king Henry IV. In January 1077 Henry crossed the Alps and waited three days in the snow outside Countess Matilda's castle at Canossa, where the pope was her guest, until he was absolved. Matilda, who ruled much of northern Italy, backed the reforming popes for decades, and 'going to Canossa' still means a humiliating climbdown.