Constantinople was the imperial capital city of the Roman Empire (330–395 A.D.), the Byzantine (Eastern Roman) Empire (395–1204 A.D. and 1261–1453 A.D.), the Latin Empire (1204–1261 A.D.), and finally the Ottoman Empire (1453–1922 A.D.). The influence of the city, also called New Rome, over the course of history is rivaled only by Jerusalem, Athens and Rome itself.
For many years during the Middle Ages Constantinople had an advanced economy and was Europe's richest and biggest urban center in the Eastern Mediterranean. This was mainly due to its strategic location (where Europe meets Asia) and its role as one of the primary ports for the famous Silk Road (route that facilitated trade between China, India, Egypt and Europe) which made it a wealthy economic hub. Byzantine Constantinople also boasted a large amount of artistic and literary treasure before it was sacked in 1204 and 1453.
Roman (Byzantine) Emperor Justinian I, in 533 A.D., began his expedition for the retaking of the former Diocese of Africa from the city. In the 730s Roman Emperor Leo III carried out extensive repairs of the city's walls, paid for by a special tax that was levied on all the subjects in the Empire.
Although attacked several times by a variety of people the city was only taken three times. In 1204 A.D. the city was taken by the army of the Fourth Crusade and in 1261 A.D. by Michael VIII. Both times the city was sacked of its significant quantity of artistic treasures. In 1453 A.D. Turkish sultan Mehmed II "the Conqueror" conquered the city for the Ottoman empire.
Under the Ottoman sultans the city was beautified with many palaces, fountains, monuments, aqueducts and other structures. After the end of World War I the Allied powers occupied Constantinople (1918 to 23 A.D.). The last Ottoman sultan was dethroned in 1922 and one year later Ankara became Turkey's new capital city. Constantinople was officially renamed Istanbul, which means "in the city" or "to the city," in 1930 A.D.