Occupation of Constantinople

Occupation of Istanbul
Part of the partition of the Ottoman Empire and the Turkish War of Independence
Louis Franchet d'Espèrey marching in Beyoğlu, 8 February 1919
Date 12 November 1918 – 4 October 1923 (4 years, 10 months, 3 weeks and 1 day) Location Constantinople Result Allied military occupation under the British, French, Italian and Greek armies dismantlement of Ottoman Empire and parliement Treaty of Sèvres Territorial changes Recognition of Turkey with Treaty of Lausanne
Belligerents
British Empire British India[1]  France French West Africa  Italy  Greece	Ottoman Empire	Turkish National Movement
Commanders and leaders
Somerset Arthur Gough-Calthorpe George Milne Louis Franchet d'Esperey Carlo Sforza[2] Efthimios Kanellopoulos (1918–1921) Charalambos Simopoulos (1921–1923)	Ali Sait Pasha¹	Selâhattin Âdil Pasha2
Strength
Land forces on 13 November 1918:[3] 2,616 British, 540 French, 470 Italian (Total: 3,626 soldiers) Land forces by 5 November 1919:[4] : 27,419 soldiers (27 artillery batteries, 160 machine guns) : 19,069 soldiers (30 cannons, 91 machine guns) : 3,992 soldiers : 795 soldiers (160 machine guns) Total: ~51,300 soldiers (411 machine guns, 57 artillery pieces) Naval forces: 13 November 1918: 50[5]–61[6] warships 15 November 1918: 167 warships+auxiliary ships[7][8]
1: Commander of the XXV Corps and the Constantinople's Guard (6 October 1919 – 16 March 1920[9]) 2: Commander of the Istanbul Command (10 December 1922 – 29 September 1923[10])

Occupation of Constantinople was a military occupation of the Ottoman capital, Constantinople (now Istanbul), following the Ottoman defeat in World War I. Though it had been de facto occupied from 12 November 1918, the official announcement for the occupation of the city was made in 16 March 1920. It was the first ever time since 1453 for the city to change hands. Later the Allied defeat in Anatolia and the subsequent Chanak Crisis led to the Armistice of Mudanya, which allowed the Turkish forces belonging to Ankara Government to enter the city for the first time. After the Treaty of Lausanne, allied forces began to evacuate the city and on September 4, 1923; last Allied forces left the city. Turkish armies officially took control of the city in 6 September 1923, which celebrated as the "Liberation day of Istanbul".