Who conquered Constantinople after it fell?
The ottoman empire in 1453.
The city was also conquered during the fourth crusade and fell c.13th April 1204 but was then re-captured by the Byzantines in 1261. On 29 May 1453 the Ottoman Empire, under the command of Sultan Mehmed II, finally conquered Constantinople; this was the end of the Byzantine Empire. Several armies, at various times. The most recent was the Turks', in AD 1453.
Constantinople was conquered by the ottoman Turks in 1453. The Turks used both the name Kostantiniyye in their official documents, and Istanbul was the was the popular name. The Europeans continued to call it Constantinople. In 1923 the Turkish government decided that Istanbul was to be the sole name of the city.