What were the reasons of rise and decline of supremacy of Church in medieval Europe? 

One of the most important reasons for the rise of Church in medieval Europe is that it was far better organized than the political establishments. The extensive and systematic organization of the Church gave it access to a great wealth. Further, Church actually provided the only real opportunity for an exceptional individual to excel and rise above the social status of his birth. The too much wealth led to corruption by the office holders of the Church and that led to loss of prestige by the end of the middle ages.

The Investiture Controversy

In 11th and 12th century, there was a significant conflict between Church and state in medieval Europe, which is known as the Investiture Controversy. Investiture Controversy refers to the challenges given by the successive Popes to the authority of the European monarchies over its authority and control of the appointments of the church officials such as bishops and abbots.

The first notable conflict was between the Pope Gregory VII and the Holy Roman Emperor Henry IV. The controversy led to affirmation of papal authority over the empire and the new canon law governing the election of the pope by the College of Cardinals. The vision of Pope Gregory VII (1073-1080) was Christendom, which in fact was established.

The Church reached the height of its power and influence under Pope Innocent III (1198-1216). In his times, the Church’s hierarchy paralleled that of ancient. The Pope occupied the position of the emperor. The bishops presided over bishoprics, as the governors had once presided over the Roman provinces. Local priests ministered to each local community. Those bishops who were geographically or politically important became archbishops. By this time, College of Cardinals, appointed by the Pope, occupied a legislative position equivalent to that once held by the Roman Senate.

The Cardinals had the responsibility to elect each new pope. The Church had its own law, canon law, and its own court system which was a rival to that of the new emerging monarchies.

The Church Doctrines

In those days, the Church was the constant link between the common man and God. The doctrine of the Church held that one could only get to heaven by doing good works and observing the sacraments. The sacraments refer to the holy seven sacraments viz. baptism, confirmation, communion, penance, holy matrimony, holy orders, and extreme unction or last rites. The Church Doctrine said that these seven sacraments would keep an individual constantly connected with God and the Church from birth to death.

The Individuals could be punished by excommunication, which refers to the process of being cut off from the Church when a person could not receive the sacraments.

Not only individuals but the Church could also punish the entire geographic areas via its interdiction which prohibited the performance of any of the sacraments in that particular geographical area. This implies that the interdiction was used as a powerful weapon against immoral, rebellious or independent feudal rulers.