The medieval church and the papacy
1048–1053 Pope Leo IX issues decrees against simony and priestly marriage, beginning the reform movement.
1059 A college of cardinals to elect new popes is established.
1075 The Lateran Council decrees that only the pope can appoint bishops.
1076 Gregory VII deposes and excommunicates Henry IV.
1084 Henry IV captures Rome, forcing Gregory VII to flee to southern Italy.
1095 The pope calls a Crusade, asserting papal leadership over Christendom.
1122 In the Concordat of Worms, Henry V gives up almost all rights to invest bishops.
For three days in 1078, the Holy Roman Emperor Henry IV stood penitent, ...