Less than two weeks after their victorious recapture of the strategically placed city of Kut-al-Amara on the Tigris River in Mesopotamia, British troops under the regional command of Sir Frederick Stanley Maude bear down on Baghdad, causing their Turkish opponents to begin a full-scale evacuation of the city on the evening of March 10, 1917.
Shortly after receiving control of regional operations in Mesopotamia in the summer of 1916, Maude began to reorganize and re-supply his troops in preparation for a renewed offensive. The central target of the operation would be the city of Kut, which had been captured by the Turks in April 1916 along with 10,000 British and Indian soldiers under the command of Sir Charles Townshend, a devastating defeat for Allied operations in the region. In January 1917, Maude's 150,000 troops set out from the regional command headquarters at Basra, located south of Kut near the junction of the Tigris with the Euphrates River, launching the offensive that would culminate in the recapture of Kut on February 24.
In the wake of their success at Kut, Maude's forces paused briefly while waiting for confirmation from headquarters in London to continue their offensive. Operations were not renewed until March 5—a pause that gave Turkish commander in chief Khalil Pasha some time to consider his options for mounting a defense of Baghdad, the capital of the Ottoman Empire's southern region. In the end, Pasha was indecisive—after first beginning preparations for an offensively minded forward assault on approaching Allied forces, he decided instead to fall back and concentrate his troops near Baghdad itself. He therefore stationed the Turkish Sixth Army some 35 miles to the south of the city, near the junction of the Tigris with the Diyala River.
In the absence of significant reserves, the Turks were vastly outnumbered, with only 9,500 soldiers facing 45,000 British and Indian troops. Maude's troops reached the Diyala on March 8, mounting their first assault on the Turkish positions the next morning, which Pasha and his men successfully repelled. After struggling to cross the fast-moving Diyala, Maude decided to shift his troops and cross the river at a more northern point. Alerted to enemy movements by German reconnaissance aircraft, Pasha mirrored his movements, sending the bulk of his forces to meet the Allied soldiers. He left a single regiment to hold the original defensive position at the Diyala, which was quickly and decisively crushed by British and Indian forces with a sudden attack on March 10. Stunned, Pasha ordered his troops to retreat. By the end of the day, the evacuation of Baghdad was underway.
After marching more than 100 miles in 15 days, Maude's troops entered Baghdad on March 11 without a struggle, taking 9,000 prisoners from the retreating Ottoman army amid cheers from the city's 140,000 occupants. The Allied victory in Baghdad marked only the beginning of the struggle over who would control the oil-rich region of Mesopotamia (the area between the Tigris and Euphrates Rivers, now Iraq and eastern Syria). The British government had earlier promised a number of Arab leaders that their people would receive their independence if they rebelled against Turkish rule; a subsequent uprising in June 1916 was led by Faisal Husein and partially engineered by the British, including Colonel T.E. Lawrence (later known as Lawrence of Arabia).
After World War I ended in November 1918, however, the Treaty of Versailles and the newly created League of Nations gave Britain a mandate to govern in Mesopotamia, and the British and French governments issued a joint declaration stating their intention to work towards establishing independent Arab governments in the former Ottoman states. This was not enough, however, for the Arabs in Mesopotamia, who began an armed uprising in 1920 against British occupation forces in Baghdad and other areas. After subduing the revolt at great expense—£40 million—the British government decided to give up its mandate, drawing up a provisional government for Iraq that included a council of Arab ministers under the supervision of a British high commissioner. In August 1921, Faisal Husein won 96 percent of the votes and was elected king of the new Iraqi nation.