Constantinople by this stage was underpopulated and dilapidated. The population of the city had collapsed so severely that it was now little more than a cluster of villages separated by fields. On 2 April 1453, Sultan Mehmed's army of 80,000 men and large numbers of irregulars laid siege to the city.
The son of Murad II, Mehmed the Conqueror, reorganized both state and military, and on 29 May 1453 conquered Constantinople, ending the Byzantine Empire. Mehmed allowed the Eastern Orthodox Church to maintain its autonomy and land in exchange for accepting Ottoman authority.
Despite a desperate last-ditch defense of the city by the massively outnumbered forces (c. 7,000 men, 2,000 of whom were foreign), Constantinople finally fell to the Ottomans after a two-month siege on 29 May 1453. The final Byzantine emperor, Constantine XI Palaiologos, was last seen casting off his imperial regalia and throwing himself into hand-to-hand combat after the walls of the city were taken.