The Byzantine Empire is technically a surviving part of the remaining Roman Empire. When the Roman Empire split, the Byzantine Empire managed to last another thousand years. It had its own Orthodox Church. Western Europe was basically dominated by the Pope of the Roman Catholic Church - his word was law. People thought that the Pope knew what God wanted, so whatever the Pope said, the people believed. Both Western Europe and The Byzantine Empire were dominantly Christian, though they did not agree on some things. Both of them traded on the old Silk Road.