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.
Fall of Constantinople
With the capture of Constantinople, Mehmed II had acquired the "natural" capital of its kingdom, albeit one in decline due to years of war. The loss of the city was a crippling blow to Christendom, and it exposed the Christian west to a vigorous and aggressive foe in the east. The Christian re-conquest of Constantinople remained a goal in Western Europe for many years after its fall to the House of Osman. Rumors of Constantine XI's survival and subsequent rescue by an angel led many to hope that the city would one day return to Christian hands. Pope Nicholas V called for an immediate counter-attack in the form of a crusade. When no European monarch was willing to lead the crusade, the Pope himself decided to go, but his early death stopped this plan. As Western Europe entered the 16th century, the age of Crusading began to come to an end.