In my paper, Roman See as Historic Standard-Bearer of Orthodoxy (+ the Ecclesiological Absurdity of Anti-Catholic-Type Eastern Orthodox Arguments Against Roman Primacy & Apostolicity) [1997], I cited five notable instances of Eastern schism before 1054: a. The Arian schisms (343-98) b. The controversy over St. John Chrysostom (404-415) c. The Acacian schism (484-519) d. Concerning Monothelitism (640-681) e. Concerning Iconoclasm (726-87 and 815-43) This information came from historian Christopher Dawson. He was referring to the Eastern, or Byzantine Empire, which was... Read more