During the early Middle Ages, popes established good relations with kings in Western Europe. However, conflicts between the papacy or the office of the pope and kings began to arise, since they both claimed to be the leaders of Western Europe. There was a controversy about who had the real power...the men of the church or the emperor? During those times, the Roman emperors had the investiture (the Holy Power) to appoint local church leaders, for example: the bishops, who had the eclesiastical authority over all the priests and believers in a city or region.
Pope Gregory initiated reforms and asserted the papal claim to primacy of jurisdiction in the Church. Gregory VII tried to establish a claim of sovereignty on the part of the Papacy. He claimed the primacy and power of the pope over political leaders, including the emperor. Consequently, there was no regal authority (except the Pope) which could command bishops, since Gregory VII had banned this practice.
