The post-war (World War I) partition of the Ottoman Empire was the subject of intense negotiations between the Allied Powers. In hindsight, each of the agreements entered into during the course of the war made sense within the war time context.
The Constantinople Agreement, May 1914
By this engagement, Britain agreed that Russia should obtain, in complete possession, Constantinople and the Straits. Britain would get a neutral zone in Persia.
Treaty of London, April 1916
Under Article 9 of the Treaty, Great Britain, France and Russia recognized that Italy would get a part of the Mediterranean region in the event of partition of Turkey in Asia adjacent to the province of Adalia. However, Italy betrayed her allies and entered the war upon the side of their enemies.
Anglo-French Agreement, May 1916 or Sykes-Picot Agreement
This agreement provided that Russia should obtain Ergerum, Van, Bitlis, Trabizond and territories in Southern Kurdistan; Great Britain would get Mesopotamia and France would have Syria and Lebanon and the villages of Adana. The Arab territories south of these areas were to be reserved as independent Arab Empire under the zone of influence of France and Britain.
St. Jean de Maurienne Conference, April 1917
Under this conference, Italy was promised some 70000 sq. miles in Asia Minor including Adana and Smyrna. This, in effect, meant placing under protection purely Turkish territory.
World War ended in 1918 with the surrender of the German Empire, the Austro-Hungarian Empire, the Ottoman Empire and the Kingdom of Bulgaria. The Ottoman Empire lay dismembered and impotent, its capital and Caliph at the mercy of Allied Powers. No other victory was so overwhelming, so unquestioned. Turkey was forced to abandon her claim to Egypt, Tripoli, Barea, the Dodecanese, the Aegean Islands and Cyprus. Turkey lost Syria, the Lebanon, Palestine and what was then known as Transjordania. She was deprived of the guardianship of the Holy places (Mecca and Medina). The provinces of the Hedgaz and the Yemen were torn from her grasp. Mesopotamia, with its vast resources declared its independence.
In 1912, the Ottoman Empire had covered 1,500,000 sq miles, and the Sultan could claim dominion over 36,000,000 people. As a result of the Balkan Wars and the European War, the Turkish State comprised only 445,609 sq. miles with a population of 13,648,270. Turkey entered the war as the powerful Ottoman Empire. She emerged from it as an Asiatic Republic, scarcely larger than the state of Hyderabad (India).
Lord Curzon's Proposals
In January 1919, Curzon had made the following proposals : The subject races of Turkey, the Arabs and the Armenians, were to be given the right of self determination and independence. The Anatolian peninsula which since the Seljuks had become the homeland of the Turkish race, was to be preserved in its integrity for the future Turkish State. There was to be no partition of Turkey proper. He had desird that the Turkish problem should once and for all be removed from European diplomacy. For this purpose an operation at once drastic and decisive should be performed. Turkey must be deprived of all European provinces; Constantinople and the Straits must be entrusted to other hands. In the words of Lord Curzon: For nearly five centuries, the presence of Turks in Europe has been a source of distraction, intrigue and corruption in European politics; of oppression and insult to the subject nationalities; and an incentive to undue and overweening ambitions in the Moslem world. Once the Turks had been expelled from Europe and an international administration established at Constantinople no Ghazi Pasha would challenge the system.
Treaty of Lausanne, July 1923
The immediate cause of declaration of war against the Ottoman in 1914 was the Ottoman's bombardment of the Russian Black Sea ports. France, Russia and Great Britain declared war against the Ottoman Empire. During the war, the Turks resorted to the persecution of the Arabs and the Armenians. Finally, under severe attack from the Allied Forces, the Ottoman signed the Armistice of Mudros on October 30, 1918. By the Treaty of Sevres, Ottomans retained Istanbul and part of Thrace, lost the Arab province and large areas of Asia Minor to a newly created Armenian state and surrendered the Islands of Imroz and Bozcada to Greece. The Straits were internationalized. This treaty was abrogated by the Treaty of Lausanne (July 1923). By this settlement the Turkish frontiers in Thrace was established on the Taritsa river and Greece returned the Islands of Imroz and Bozcaada. Turkey got control of the Straits in 1936.
Legitimacy of the Middle Eastern Frontiers
The legitimacy of the Middle Eastern frontier has been called into question since they were first drafted. Arab nationalists in the 1940s and 1950s openly called for unity schemes between Arab states that would overthrow boundaries drawn by western imperial powers. In 2014, the Islamic State tweeted to its followers that it was smashing Sykes-Picot when it declared a Caliphate in territory spanning northern Syria and Iraq, says Rogan.