System of central government of the Roman Catholic church. Bishops led the early church, the bishop of Rome being accorded special respect by the end of the 1st century AD in part because of the belief that St. Peter was the first bishop of that city. St. Cyprian challenged that position of honour in the 3rd century, and in the 4th–5th century the power of the see of Constantinople rose to challenge that of Rome; the rivalry would culminate in the Schism of 1054 between the Eastern and Western churches. After the collapse of the Roman Empire, the papacy found protection under the wing of Charlemagne and his successors; in the 9th–10th century the German emperors controlled it. In 1059 Pope Nicholas II responded by vesting the right to name a new pope exclusively with the College of Cardinals. To establish the papacy's supremacy in Christian society, Gregory VII excommunicated Henry IV of Germany for disobedience to papal commands and decreed that civil rulers could not invest churchmen with temporal power (seeInvestiture Controversy). In the next centuries, the papacy developed into one of the most important and influential institutions in Europe, and Urban II, Innocent III, and Gregory IX were among the most significant popes of the period. The worldliness and corruption of the papal court that emerged at the same time and the Babylonian Captivity of the papacy at Avignon (seeAvignon papacy) led to the Western Schism and eventually to the Reformation. The Council of Trent inaugurated the Counter-Reformation. In the 19th century the papacy lost its remaining temporal powers when the Papal States were incorporated into the new Kingdom of Italy. It maintained a conservative religious position, proclaiming infallibility in doctrinal matters and espousing the idea that the pope is the absolute ruler of the church. The Second Vatican Council gave the bishops, clergy, and laity more voice. See alsoRoman Catholicism.