Ecclesiastical differences between the Catholic Church and the Eastern Orthodox Church

The disputes were a major factor in the formal East-West Schism between Pope Leo IX and Patriarch Michael I in 1054 and are largely still unresolved between the churches today.

The Orthodox insist that it should be a "primacy of honor", as in the ancient church and not a "primacy of authority",[1] whereas the Catholic Church sees the pontiff's role as requiring for its exercise power and authority the exact form of which is open to discussion with other Christians.

[2] The declaration of Ravenna in 2007 re-asserted these beliefs and re-stated the notion that the bishop of Rome is indeed the protos ("first" in Greek), although future discussions are to be held on the concrete ecclesiastical exercise of papal primacy.

Hierarchs within the Russian Church have condemned the document and reassert that Papal authority as is held in the West is not historically valid.

In practice, this has sometimes led to divisions among Greek, Russian, Bulgarian and Ukrainian Orthodox churches, as no central authority can serve as a rallying point for various internal disputes.

However, in contrast with the picture presented by the Russian religious poet Aleksey Khomyakov more than a century earlier,[9] the Catholic Church's Second Vatican Council reasserted the importance of collegiality, clarifying that "primatial authority is inseparable from collegiality and synodality" and that "the Bishop of Rome is a brother among brothers who are sacramentally all equal in the episcopate.