The British Mandate of Mesopotamia (الانتداب البريطاني على العراق) was a League of Nations Class A mandate under Article 22 and entrusted to Britain when the Ottoman Empire was divided in August 1920 by the Treaty of Sèvres following World War I. This award was prepared on April 25 1920, at the San Remo conference in Italy. France controlled the Mandates of Lebanon and Syria. Faisal ibn Husayn, who had been proclaimed king of Syria by a Syrian national congress in Damascus in March 1920, was ejected by the French in July of the same year.
The civil government of postwar Iraq was headed originally by the high commissioner, Sir Percy Cox, and his deputy, Colonel Arnold Wilson. British reprisals after the murder of a British officer in Najaf failed to restore order. British administration had yet to be established in the mountains of Kurdistan. From the Hakkari Mountains beyond Iraq's northern frontier and from the plains of Urmia in Iran, thousands of Assyrians began to pour into Iraqi territory seeking refuge from Turkish savagery (see also Assyrian independence). The most striking problem facing the British was the growing anger of the nationalists, who felt betrayed at being accorded mandate status.
The grand mujtahid of Karbala, Imam Shirazi, and his son, Mirza Muhammad Riza, began to organize the insurgent effort. Shirazi then issued a fatwa (religious ruling), pointing out that it was against Islamic law for Muslims to countenance being ruled by non-Muslims, and he called for a jihad against the British. By July 1920, Mosul was in rebellion against British rule, and the insurrection moved south down the Euphrates River valley. The southern tribes, who cherished their long-held political autonomy, needed little inducement to join in the fray. They did not cooperate in an organized effort against the British, however, which limited the effect of the revolt. The country was in a state of anarchy for three months; the British restored order only after using chemical weapons dropped from Royal Air Force bombers.
Ath Thawra al Iraqiyya al Kubra, or the Great Iraqi Revolution of 1920, was a watershed event in contemporary Iraqi history. For the first time, Sunnis and Shias, tribes and cities, were brought together in a common effort. In the opinion of Hanna Batatu, author of a seminal work on Iraq, the building of a nation-state in Iraq depended upon two major factors: the integration of Shias and Sunnis into the new body politic and the successful resolution of the age-old conflicts between the tribes and the riverine cities and among the tribes themselves over the food-producing flatlands of the Tigris and the Euphrates. The 1920 rebellion brought these groups together, if only briefly; this constituted an important first step in the long and arduous process of forging a nation-state out of Iraq's conflict-ridden social structure.
The final major decision taken at the Cairo Conference related to the new Anglo-Iraqi Treaty of 1922. Faisal was under pressure from the nationalists and the anti-British mujtahids of Najaf and Karbala to limit both British influence in Iraq and the duration of the treaty. Recognizing that the monarchy depended on British support— and wishing to avoid a repetition of his experience in Syria — Faisal maintained a moderate approach in dealing with Britain. The treaty which had been originally set as a twenty year engament but later reduced to 4 years, was ratified in June 1924, stated that the king would heed British advice on all matters affecting British interests and on fiscal policy as long as Iraq had a balance of payments deficit with Britain, and that British officials would be appointed to specified posts in eighteen departments to act as advisers and inspectors. A subsequent financial agreement, which significantly increased the financial burden on Iraq, required Iraq to pay half the cost of supporting British resident officials, among other expenses. British obligations under the new treaty included providing various kinds of aid, notably military assistance, and proposing Iraq for membership in the League of Nations at the earliest moment. In effect, the treaty ensured that Iraq would remain politically and economically dependent on Britain. While unable to prevent the treaty, Faisal clearly felt that the British had gone back on their promises to him.
The British decision at the Cairo Conference to establish an indigenous Iraqi army was significant. In Iraq, as in most of the developing world, the military establishment has been the best organized institution in an otherwise weak political system. Thus, while Iraq's body politic crumbled under immense political and economic pressure throughout the monarchic period, the military gained increasing power and influence; moreover, because the officers in the new army were by necessity Sunnis who had served under the Ottomans, while the lower ranks were predominantly filled by Shia tribal elements, Sunni dominance in the military was preserved.
Beginning in 1923, British and Iraqi negotiators held acrimonious discussions over the new oil concession. The major obstacle was Iraq's insistence on a 20 percent equity participation in the company; this figure had been included in the original TPC concession to the Turks and had been agreed upon at Sanremo for the Iraqis. In the end, despite strong nationalist sentiments against the concession agreement, the Iraqi negotiators acquiesced to it. The League of Nations was soon to vote on the disposition of Mosul, and the Iraqis feared that, without British support, Iraq would lose the area to Turkey. In March 1925, an agreement was concluded that contained none of the Iraqi demands. The TPC, now renamed the Iraq Petroleum Company (IPC), was granted a full and complete concession for a period of seventy-five years.
The new Anglo-Iraqi Treaty was signed in June 1930. It provided for a "close alliance," for "full and frank consultations between the two countries in all matters of foreign policy," and for mutual assistance in case of war. Iraq granted the British the use of air bases near Basra and at Al Habbaniyah and the right to move troops across the country. The treaty, of twenty-five years' duration, was to come into force upon Iraq's admission to the League of Nations. This occurred on October 3, 1932.