After the Great Schism occurred, what major difference separated the Eastern Orthodoxy and the Catholic faith?

Question:

After the Great Schism occurred, what major difference separated the Eastern Orthodoxy and the Catholic faith?

Explanation:

Charlemagne's crowning made the Byzantine Emperor redundant, and relations between the East and the West deteriorated until a formal split occurred in 1054. The Eastern Church became the Greek Orthodox Church by severing all ties with Rome and the Roman Catholic Church — from the pope to the Holy Roman Emperor on down.