They're using different languages, Latin versus Greek. You now have the Western pope recognizing a different, as you could say, Roman emperor in Charlemagne. The nature of the West is becoming more Germanic and using the language Latin, while the nature of the East is continuing in Greek traditions. On top of that, what you have in the year 800, you're actually in this period where you've had several conflicts over this notion of iconoclasm. This iconoclasm movement, you could say, started in 726 when the Byzantine emperor said, enough of these images of Jesus and the Virgin Mary and other figures of Christianity in our churches, citing references in the Old Testament saying that, hey, we shouldn't have these images. And so this conoclasm, or these destroying of icons, starts to begin. Well, the pope in the West, they say, hey, we don't think we have to listen to you.