Constantinople, situated between East and West, was for many Europeans emblematic of the entire Eastern world. The city has been occupied for over 2,500 years, although the modern city was Roman in origin. Early in the fourth century, the Emperor Constantine named Constantinople the capital of his newly Christian empire. After the fifth-century fall of Rome, however, Istanbul was subject to repeated invasions and conquests by Persians, Arabs, Bulgars, Russians, and Western European Christians in the Fourth Crusade. In 1453, the city was taken by Mehmed II and made the new capital of the Ottoman Empire, a position it held until after the First World War.