This event "divided the 'Chalcedonian' Christianity into Western (Roman) Catholicism and Eastern Orthodoxy... The East-West Schism was the result of extended period of estrangement between the two bodies of churches. The primary causes of the Schism were disputes over papal authority -- the Roman Pope claimed he held authority over the four Eastern patriarchs, while the four eastern patriarchs claimed that the primacy of the Patriarch of Rome was only honorary, and thus he had authority only over Western Christians -- and over the insertion of the filioque clause into the Nicene Creed... The Church split along doctrinal, theological, linguistic, political, and geographic lines, and the fundamental breach has never been healed. It might be alleged that the two churches actually reunited in 1274 (by the Second Council of Lyons) and in 1439 (by the Council of Basel), but in each case the councils were repudiated by the Orthodox as a whole, given that the hierarchs had overstepped their authority in consenting to these so-called 'unions'. Further attempts to reconcile the two bodies have failed; however, several ecclesiastical communities that originally sided with the East changed their loyalties, and are now called Eastern Rite Catholic Churches. For the most part, however, the Western and the Eastern Churches are separate. Each takes the view that it is the "One Holy Catholic and Apostolic Church", implying that the other group left the true church during the Schism," (https://www.theopedia.com/great-schism).