British Mandate for Mesopotamia (legal instrument) in the context of "League of Nations Mandate"

The partition of the Ottoman Empire (30 October 1918 – 1 November 1922) was a geopolitical event that occurred after World War I and the occupation of Constantinople by British, French, and Italian troops in November 1918. The partitioning was planned in several agreements made by the Allied Powers early in the course of World War I, notably the Sykes–Picot Agreement, after the Ottoman Empire had joined Germany to form the Ottoman–German alliance. The huge conglomeration of territories and peoples that formerly comprised the Ottoman Empire was divided into several new states. The Ottoman Empire had been the leading Islamic state in geopolitical, cultural, and ideological terms. The partitioning of the Ottoman Empire after the war led to the domination of the Middle East by Western powers such as Britain and France, and saw the creation of the modern Arab world and the Republic of Turkey. Resistance to the influence of these powers came from the Turkish National Movement but did not become widespread in the other post-Ottoman states until the period of rapid decolonization after World War II.

The League of Nations mandate granted the French Mandate for Syria and the Lebanon, the British Mandate for Mesopotamia (later Iraq) and the British Mandate for Palestine, later divided into Mandatory Palestine and the Emirate of Transjordan (1921–1946). The Ottoman Empire's possessions in the Arabian Peninsula became the Kingdom of Hejaz, which the Sultanate of Nejd (today Saudi Arabia) was allowed to annex, and the Mutawakkilite Kingdom of Yemen. The Empire's possessions on the western shores of the Persian Gulf were variously annexed by Saudi Arabia (al-Ahsa and Qatif), or remained British protectorates (Kuwait, Bahrain, and Qatar) and became the Arab States of the Persian Gulf.

The Hashemite Kingdom of Iraq was the Iraqi state located in the Middle East from 1932 to 1958. It was founded on 23 August 1921 as the Kingdom of Iraq, following the defeat of the Ottoman Empire in the Mesopotamian campaign of the First World War. Although a League of Nations mandate was awarded to the United Kingdom in 1920, the 1920 Iraqi revolt resulted in the scrapping of the original mandate plan in favour of a formally sovereign Iraqi kingdom, but one that was under effective British administration. The plan was formally established by the Anglo-Iraqi Treaty.

The role of the United Kingdom in the formal administration of the Kingdom of Iraq was ended in 1932, following the Anglo-Iraqi Treaty (1930). Now officially a fully independent kingdom, officially named the Hashemite Kingdom of Iraq, it underwent a period of turbulence under its Hashemite rulers throughout its entire existence. Establishment of Sunni religious domination in Iraq was followed by Assyrian, Yazidi and Shi'a unrests, which were all brutally suppressed. In 1936, the first military coup took place in the Hashemite Kingdom of Iraq, as Bakr Sidqi succeeded in replacing the acting Prime Minister with his associate. Multiple coups followed in a period of political instability, peaking in 1941.

The Anglo-Iraqi Treaty of October 1922 was an agreement signed between the British and Iraqi governments. The treaty was designed to allow for Iraqi self-government while giving the British control of Iraq's foreign policy. It was intended to conclude an agreement made at the Cairo Conference of 1921 to establish a Hashemite Kingdom in Iraq.

In the aftermath of the First World War, the former possessions of the Ottoman Empire were divided between France and Britain, with the remainder becoming the present-day country of Turkey. The former Ottoman provinces of Baghdad, Mosul, and Basra were proposed to become a League of Nations Class A mandate under direct British rule, known as the British Mandate for Mesopotamia. The general public in the region reacted negatively to the mandate, resenting the imposition of British control; this led to the Iraqi revolt of 1920, which caused the British to instead decide that the mandate territories would instead become the Kingdom of Iraq. On 23 August 1921, Faisal ibn Hasayn was crowned as Faisal I, King of Iraq.