Constantinople
Constantinople (; ) was the capital city of the Roman/Byzantine Empire (330–1204 and 1261–1453), and also of the brief Crusader state known as the Latin Empire (1204–1261), until finally falling to the Ottoman Empire (1453–1923). It was reinaugurated in 324 from ancient Byzantium as the new capital of the Roman Empire by Emperor Constantine the Great, after whom it was named, and dedicated on 11 May 330. The city was located in what is now the European side and the core of modern Istanbul.
Istanbul
Constantinople began to decline continuously after the end of the reign of Basil II in 1025. The final blow was given by the conquest of Villardouin and Enrico Dandolo in 1204 during the Fourth Crusade, where the City was sacked and pillaged. The city subsequently became the center of the Latin Empire, created by Catholic crusaders to replace the Orthodox Byzantine Empire. Hagia Sophia was converted to a Catholic church in 1204. The Byzantine Empire was restored, albeit weakened, in 1261. Constantinople's churches, defenses, and basic services were in disrepair, and its population had dwindled to a hundred thousand from half a million during the 8th century. After the reconquest of 1261, however some of the city's monuments were restored, and some, like the two Deisis mosaics in Hagia Sofia and Kariye, were created.