linguistic:translation
Religious and cultural influence

After the East–West Schism of 1054, significant parts of Eastern Europe developed cultural unity and resistance to Catholic Western and Central Europe within the framework of the Eastern Orthodox Church, Church Slavonic language and the Cyrillic alphabet.

The earliest concept of Europe as a cultural sphere (instead of simply a geographic term) was formed by Alcuin of York during the Carolingian Renaissance of the 9th century, limited to the territories that practised Western Christianity at the time. "European" as a cultural term did not include much of the territories where the Orthodox Church represented the dominant religion until the 19th century.

A large section of Eastern Europe is formed by countries with dominant Orthodox churches, like Belarus, Bulgaria, Cyprus, Georgia, Greece, Moldova, Montenegro, North Macedonia, Romania, Russia, Serbia, and Ukraine, for instance, as well as Armenia, which is predominantly Armenian Apostolic. The Eastern Orthodox Church has played a prominent role in the history and culture of Eastern and Southeastern Europe. To a lesser degree, forms of Eastern Protestantism and Eastern Catholicism have also been influential in Eastern Europe. Countries where Eastern Protestantism or Eastern Catholicism hold historical significance include Belarus, Croatia, Greece, Hungary, Lithuania, Poland, Romania, Russia, Slovakia, Slovenia and Ukraine.

The schism refers to the historical break of communion and theology between the Eastern (Orthodox) and Western (Catholic) churches. Later developments meant that the divide was no longer solely between Catholic and Orthodox churches. From the 16th century, both Western and Eastern forms of Protestantism began to emerge in Europe. Additionally, Eastern Catholic Churches began to spread in Europe during the 16th and 17th centuries, following the establishment of the Ukrainian Greek Catholic Church in 1596. However, the concept of Eastern Catholicism itself predates this.

Since the Great Schism of 1054, Europe has been divided between Catholic (and later additionally Protestant) churches in the West, and the Eastern Orthodox Christian (often incorrectly labelled "Greek Orthodox") churches in the east. Due to this religious cleavage, Eastern Orthodox countries are often associated with Eastern Europe. A cleavage of this sort is, however, often problematic; for example, Greece is overwhelmingly Orthodox, but is very rarely included in "Eastern Europe", for a variety of reasons, the most prominent being that Greece's history, for the most part, was more influenced by Mediterranean cultures and dynamics.