As we go even further in time, as we enter into the second millennium, we can see that the Muslim Turks make further inroads into the Byzantine Empire. Also during the Fourth Crusades, Western crusaders sack Constantinople. And we can go all the way to 1453, where all that was left at the time of the Byzantine Empire, or you could say the Eastern Roman Empire, is Constantinople. And in 1453, that also gets sacked by the Ottomans. And that's the official end of the Byzantine Empire, the Eastern Roman Empire, which you can see continues on for another thousand years after the fall of the Western Roman Empire. Now with that review out of the way, let's think about how the Byzantine Empire was the same and different from the Roman Empire. So first let's think about the center of power.