Actually, the Roman Empire did not collapse in 476 AD. While the western half of the empire fell to the Germanic tribes, the Eastern Roman Empire, also known as the Byzantine Empire, continued for almost a millennium. In the 6th century, the Roman empire under Emperor Justinian regained control of Italy, the former heartland of the Empire. It was not until Constantinople fell to the Ottomans in 1453 that the Roman Empire definitively ceased to exist.