We've talked about the notion of philoque. And those aren't all of the issues. On top of that, you have this notion of leavened and unleavened bread, wherein the west, in their mass, when they are consecrating the bread to be viewed as the body of Christ, they used unleavened bread based on the belief that this is what Christ used during the Last Supper. And the east, they said, no, we have agreed to use leavened bread. And so this is one further tension, even more than the actual issues, are the sense of, well, why do you think you have the right to tell me what to do? And as we get into 1053, you have what are known as the Latin churches in Constantinople being shut down by the Patriarch of Constantinople, Patriarch Serularius or Carularius, saying that, hey, these guys are going against what is actually acceptable in Christianity. Now, in retaliation, you have Pope Leo IX shutting down what would be known as Greek churches and how they practice in the Italian Peninsula, either closing them down or forcing them to practice the way the Latins practice.