During the reign of Conrad II's son, Henry III (1039 to 1056), the empire supported the Cluniac reforms of the Church, the Peace of God, prohibition of simony (the purchase of clerical offices), and required celibacy of priests. Imperial authority over the Pope reached its peak. However, Rome reacted with the creation of the College of Cardinals and Pope Gregory VII's series of clerical reforms. Pope Gregory insisted in his "Dictatus Papae" on absolute papal authority over appointments to ecclesiastical offices. The subsequent conflict in which emperor Henry IV was compelled to submit to the Pope at Canossa in 1077, after having been excommunicated came to be known as the Investiture Controversy. In 1122 a temporary reconciliation was reached between Henry V and the Pope with the Concordat of Worms. With the conclusion of the dispute the Roman church and the papacy regained supreme control over all religious affairs. Consequentlly the imperial Ottonian church system ("Reichskirche") declined. It also ended the royal/imperial tradition of appointing selected powerful clerical leaders to counter the Imperial secular princes.