Jesus talked of everlasting damnation, but he gave no systematic account of what happens to those who die before the Age to Come arrives. Many early Christians believed in some form of reincarnation, but that the idea fell out of favour in the sixth century.
In 1054 papal legate Cardinal Humbert marched into the Orthodox Cathedral of Hagia Sophia in Constantinople and banged a bull of excommunication onto the altar. The Greek emperor tried to reconcile the two sides to no avail. The split between the churches dates from then.