Christian denomination

===Middle Ages===
{{Unreferenced section|date=March 2024}}
{{main|East-West Schism}}
[[File:Lutherstadt Wittenberg 09-2016 photo06.jpg|thumb|The front door of [[All Saints' Church, Wittenberg|All Saints' Church]] in [[Wittenberg]], Germany, where [[Martin Luther]] nailed his ''[[Ninety-five Theses]]'' on 31st October 1517, sparking the [[Protestant Reformation|Reformation]]]]
In Western Christianity, a handful of geographically isolated movements preceded the spirit of the [[Protestant Reformation]]. The [[Cathars]] were a very strong movement in medieval southwestern France, but did not survive into modern times. In northern [[Italy]] and southeastern [[France]], [[Peter Waldo]] founded the [[Waldensians]] in the 12th century. This movement has largely been absorbed by modern-day Protestant groups. In [[Bohemia]], a movement in the early 15th century by [[Jan Hus]] called the [[Hussite]]s  defied Catholic [[dogma]], creating the still-extant [[Moravian Church]], a major Protestant denomination.

Although the church as a whole did not experience any major divisions for centuries afterward, the Eastern and Western groups drifted until the point where patriarchs from both families [[excommunication|excommunicated]] one another in about 1054 in what is known as the [[East-West Schism|Great Schism]]. The political and theological reasons for the schism are complex, but one major controversy was the inclusion and acceptance in the West of the [[filioque clause]] into the [[Nicene Creed]], which the East viewed as erroneous. Another was the definition of [[Primacy of the Roman Pontiff|papal primacy]].

Both West and East agreed that the Patriarch of Rome was owed a "[[Primus inter pares|primacy of honour]]" by the other patriarchs (those of [[Alexandria]], [[Antioch]], [[Constantinople]] and [[Jerusalem in Christianity|Jerusalem]]), but the West also contended that this primacy extended to jurisdiction, a position rejected by the Eastern patriarchs. Various attempts at dialogue between the two groups would occur, but it was only in the 1960s, under Pope [[Paul VI]] and [[Patriarch Athenagoras]], that significant steps began to be made to mend the relationship between the two.