Byzantium was an ancient Greek city founded in 667 BC. It was besieged and taken by Rome in 196 AD and rebuilt by the emperor Septimius Severus. In 330 AD the Roman Emperor (and first Christian Emperor) Constantine I built an imperial residence there, modelling it on Rome as the new capital of the Empire. After his death the city took his name, becoming Constantinople. When the Roman Empire split, Constantinople remained the capital of the Eastern Roman Empire (the Byzantine Empire). Constantinople was a very powerful city, sitting on the route between Europe and Asia, and controlling the passage from the Mediterranean to the Black Sea. It was a centre of art, learning and culture for hundreds of years. In 1453, the city was besieged and captured by the Ottoman Turks and became the capital of the Ottoman Empire. Today it is the capital of modern Turkey and is called Istanbul.