He also moves the capital to, officially moves the capital of the entire empire to what at the time was Byzantium, but then he renames it to Constantinople, named after him. Now it was still one unified empire. Even Diocletian, who co-ruled with a co-emperor, he had veto power over the emperor to the west. Now as we get further into the fourth century here, and especially into the fifth century, we'll see that the empire further and further fragments and gets diluted and really just breaks down. One major factor in that breakdown is in that fourth century, in the fourth and fifth centuries, you have a group called the Huns coming in from Central Asia, coming in from Northern Europe right over here, and they are fierce nomadic conquerors. And they're so fierce that they start pushing more of the Germanic tribes across the Rhine and the Danube. And a lot of these Germanic tribes, at first, even though their history has been fighting the Romans, a lot of them try to seek refuge in the Roman Empire, and they're given refuge in the Roman Empire, but while they have that refuge, they're treated very, very, very badly.