The term Great Schism can refer, in the history of Christianity alone, to two separate events. They are from two distinct periods. It is usual for writers on both periods to refer to the one within their view as 'The Great Schism'. More general writers should be careful to distinguish which one they mean. Not all do.
- The first is The Great (East-West) Schism of 1054, the culmination of centuries of disagreement between the two theological traditions of Christianity based one in the East, at Constantinople, or Byzantium, and the other in the west, at Rome. These became the Orthodox and the Catholic churches.
- The second is the Great (Western) Schism, and refers to a split within the Catholic church. This is the period between 1378 and 1417 when there were two 'popes', one administering the territories loyal to him from Avignon, where 'his' papacy had moved under French political pressure (the Avignon papacy), and the other administering the territories loyal to him from Rome. In 1378, the people of Rome persuaded the Cardinals of the Sacred College to elect Urban VI (1318-1389, reigned 1378-89) by riot and threats as Bishop of Rome (= Pope). His behaviour alienated many, and the French Cardinals withdrew to Avignon and elected Clement (VII), the first Antipope of the Great (Western) Schism.
Of the two 'Great Schisms', the East-West Schism is undoubtedly the greater, in terms of splitting the whole of Christianity into two blocks and of continuity: it has lasted from 1054 to the present day, although the anathemas of 1054 were nullified in 1965. However, the Schism of the West, although it only lasted 39 years, and only split one block of Christianity, is in the foreground of the mental picture held by most Europeans, and will continue to be called 'The' Great Schism by many.