Answer: Byzantine Empire
Explanation: Constantine the Great chose the ancient city of Byzantium, for the new capital of the Roman Empire 324 AD. This city was then renamed to Constantinople 330 AD in honour of Emperor Constantine, and after the division of the empire, it became the capital of the Eastern Roman Empire. This Eastern Roman Empire was known in the Middle Ages as the Byzantine Empire, which took place about 1,000 years after the fall of the Western Roman Empire.