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.
Ancient Rome
The West responded with the Crusades, eventually resulting in the Sack of Constantinople by participants of the Fourth Crusade. The conquest of Constantinople in 1204 fragmented what remained of the Empire into successor states; the ultimate victor was the Empire of Nicaea. After the recapture of Constantinople by Imperial forces, the Empire was little more than a Greek state confined to the Aegean coast. The Byzantine Empire collapsed when Mehmed the Conqueror conquered Constantinople on 29 May, 1453.