The Investiture Controversy 

The Investiture Controversy was a conflict between the Church and the state in medieval Europe over the ability to appoint bishops and abbots of monasteries the Pope himself. The conflict took part in the 11th century, but its origins date back to the 9th century.

A medieval king investing a bishop in office 

On December 25th, 800 AD, the Frankish King Charlemagne was crowned Emperor by Pope Leo III. As a result, the new Emperor attracted the majority of the clergymen in his Empire, and they were granted rights to govern cities and provinces. The reasons behind this move are quite simple: clergymen were educated and they couldn't pass their titles. However, Charlemagne decided to invest many laymen as bishops, which drew many criticism.

 

Pope Leo III crowning Charlemagne

Over the next 2 centuries, the sins of simony and nicholaism corrupted the church, and there were calls for reforms. In 1046, 3 cardinals, Benedict IX, Sylvester II, Gregory VI, competed in order to become the new Pope. In the end, Henry III the Black, King of the Germans, supported a fourth cardinal and in the Council of Sutri, Suidger von Morsleben was elected as Pope Clement II. The new Pope also crowned Henry as Holy Roman Emperor. This was a precedent because it was the first time when a German monarch influenced the election of the Pope. Moreover, the next 3 popes after Clement were all Germans. 

Holy Roman Emperor Henry III

Pope Clement II

In 1056, Henry III passed away. He was followed by his 6-year-old son, Henry IV. In 1059, Pope Nicholas II passed a Papal Bull in which he consolidated the power of the Papacy, thus reducing the Imperial influence. Furthermore, future Popes will be elected by a Papal conclave. In 1061, Nicholas died and Pope Alexander III was elected. However, the Imperials supported an Anitpope, named Honorius II. He managed to overthrow Nicholas and claim the power in Rome, but he lost his support quickly and fled. 

In 1073, Pope Gregory VII was elected. He was a staunch anti-Imperialist, and in 1075 he issued the 'Dictatus Papae'. This document stipulated that only the Pope could appoint/dismiss bishops. Additionally, Pope had power to depose the Holy Roman Empire.

Pope Gregory VII

Dictatus Papae 

This decision was not without repercussions. In 1076, Henry IV called a synod in which he did not acknowledge Pope Gregory VII. In retaliation, Pope excommunicated the Emperor. Noticing that he had little support, Henry decided to meet the Pope in person to beg forgiveness. In 1077, the 2 met at the Castle of Canossa, Tuscany, and they made peace. 

Henry IV and Pope Gregory VII

The peace did not last for too long. In 1080, Henry faced a second excommunication, but this time he had consolidated his power and he decided to fight back. So, he supported Antipope Clement III, in 1084. Left without allies, Gregory fled Rome and died a year later. Even so, the new Antipope faced a lot of opposition in Rome, and he could not assert his power. In the end, the Investiture Controversy ended in 1125, when Holy Roman Emperor Henry V and Pope Callixtus II signed the Concordat of Worms.