Who crowned bishops nearly split empire from papacy
The Investiture Controversy (1076–1122) was a Church–state fight over appointing bishops and abbots, ignited between Pope Gregory VII and King—later Emperor—Henry IV. The Concordat of Worms under Callixtus II and Henry V let churchmen choose prelates while rulers still took fealty for temporal lands.
After Rome's western empire fell, bishops and abbots were in practice installed by lay nobles, even though that was supposedly a church task. Many prelates came from noble families themselves: under primogeniture the eldest son took the title, so younger sons often sought high church office, especially where a family had founded a church or abbey on its own estate. Because bishoprics carried great wealth and land, selling them, known as simony, was a lucrative business for the aristocracy.
The stakes for the German crown were enormous. Since Otto the Great, who ruled from 936 to 972, bishops had been princes of the empire and feudal lords over wide districts. They served as the emperor's working council, and the troops their dioceses supplied were the backbone of imperial armies, so loyalty in those posts mattered more than almost anything. Ottonian rulers even believed they should appoint the pope, and before 1059 many popes were effectively chosen by kings and rubber-stamped by electors. In the mid-eleventh century Henry III named and removed three popes within a few years.
Reformers wanted better-educated and more devout clergy, and they also wanted Rome's authority back. The open clash came in 1076 between Pope Gregory VII and Henry IV, then king and later emperor; Gregory's excommunication of Henry temporarily crippled his military position. A parallel dispute between Pope Paschal II and Henry I of England from 1103 to 1107 was settled by the Concordat of London.
The German struggle ended nearly fifty years later, in 1122, when Callixtus II and Henry V agreed the Concordat of Worms on similar lines. The church would choose bishops and invest them with ring and staff, the symbols of spiritual office, while bishops swore fealty to the ruler for their lands. In Germany, though not in Italy or Burgundy, the emperor could still attend elections and settle disputes, and emperors gave up any right to choose the pope.
Source: Investiture Controversy
