Three theories were current during the later Middle Ages regarding the relations between the pope and the German emperor. One was the theory maintained at Rome that the Church was superior to the State and that therefore the emperor had no right to interfere with the papacy. The second was the imperial theory that the State was ordained of God to protect the Church. The third was a theory that each was supreme in its own realm and should work harmoniously with the other. The third seemed impossible to achieve, and for more than a century the champions of the other two principles struggled to win a decisive victory over each other. At a synod held in Rome in 1075, Gregory VII condemned, among other things, lay investiture where a secular ruler could appoint a bishop or priest. But the German emperor, Henry IV, retaliated immediately. He summoned a council of German bishops at Worms, at which the pope was condemned and deposed. Gregory retaliated by excommunicating Henry and pronouncing him deposed. The absurdity of all this was that neither side could carry out the decisions personally against the other. The German people, however, did not support Henry and he was compelled to go in submission to the pope and seek his pardon at Canossa. Here he stood barefoot in the snow of the Apennines until Gregory had satisfied his revenge and let him in.
Impact: Once absolved the emperor hurried home, raised an army, and marched on Rome. The pope was aided by the Normans but the contest proved disastrous for Gregory and he died in exile. The quarrel continued until Henry V of Germany compromised with Pope Calixtus II in 1122 and the investiture controversy was settled for a time.