In January 1077, before the walls of the castle of Canossa, in the Emilian Apennines amidst the snow and ice, a man waits barefoot. It is the Holy Roman Emperor, Henry IV, who is the most powerful ruler in Europe. On the other side of the walls stands Pope Gregory VII, who has excommunicated the emperor. In the Middle Ages, excommunication was not just a religious matter, but a political sentence. An excommunicated king loses legitimacy, and his subjects can rebel, while his allies can abandon him. This is precisely what is happening.
The conflict arises from a seemingly technical question: who has the right to appoint bishops? The emperor or the pope? It is the Controversy over Investiture. For Henry IV, it was an imperial right, while for Gregory VII, it was an intolerable abuse. The Church must be free from the control of sovereigns. In 1076, Henry IV declared the pope deposed, but Gregory VII responded with excommunication. The German princes seized the opportunity and threatened to elect a new king if the excommunication was not revoked. Time was running out, and Henry IV had to obtain the pope's pardon, so he crossed the Alps in the dead of winter with a few trusted men. It was a forced march toward humiliation.
He arrived in Canossa, where the pope had taken refuge under the protection of Matilda of Canossa, one of Italy's most powerful figures, but the gates remained closed. For three days, Henry waited barefoot and in the cold. It was a calculated gesture, but also a desperate one. An emperor publicly bowing to save his throne. Finally, Gregory VII relented, and on January 28, 1077, he lifted the excommunication. Henry is readmitted into the Christian community, and his legitimacy is restored.
Canossa, however, is a truce, and a few years later the conflict resumes. Henry IV will once again clash with the papacy, marching on Rome and imposing an antipope, but the Canossa episode enters history as a symbol, not because it resolved the conflict between the empire and the Church (which would continue for a long time), but because it marks a precise moment, namely, when spiritual power manages to subdue political power. But this served to save the emperor, who reasserted his power in Germany and returned to the charge against the papacy.