The significance of the Investiture Controversy was that it solidified the Pope’s control over many secular leaders, the most important of which was the Holy Roman Emperor, Henry IV. The Investiture Controversy signaled the beginning of the centralization of the Church/Pope’s power. The Controversy also oversaw the first excommunication of a secular leader.
Many secular (non-religious based) leaders had appointed church bishops in the areas and lands they controlled. This appointment process was called “investiture.” Henry IV, like his predecessors and contemporary rulers, appointed bishops. The Pope, Gregory VII, wanted to central the authority of the Church in the appointment of bishops and thusly claimed the power to appoint bishops.
The Investiture Controversy reached its zenith in 1075, when the Church formally prohibited secular leaders from appointing bishops. Henry refused to adhere to the new law and continued appointing bishops. As a result, Henry was excommunicated (banished from the Church and prohibited from interacting with other Christians). Furthermore, Gregory encouraged the German nobles to disregard Henry’s orders and authority since he had been officially excommunicated. Many German nobles followed the Pope’s advice and threatened open rebellion against Henry.
Facing challenges from the Church and his nobles, Henry sought the Pope’s forgiveness and the Church’s blessing. Henry met Gregory at Canossa (allegedly in peasant garb and barefoot) and received the Pope’s forgiveness. However, once he received his welcome back into the Christian faith, Henry continued to invest his own bishops.
The Investiture Controversy continued until 1122, when the Church and the Holy Roman Emperor agreed to the Concordat of Worms. Under this agreement, the Holy Roman Emperor could still appoint bishops but the Pope still approved the appointment, giving the position its spiritual authority.
The Concordat officially ended the investiture process that secular leaders had exercised without church approval. From 1122 onward, secular leaders had to have religious approval in the appointment of bishops. The Concordat however, was not a complete victory for the Church. Secular leaders still had some say (albeit minor) in bishopric appointments.