Given the extensive overseas imperial commitments of many of the combatants, the First World War inevitably took on global dimensions. By the end of 1914, it had already touched parts of Africa, German-owned islands in the Pacific Ocean, and the coast of South America, where German and British naval forces clashed at the Battle of the Falklands and the Battle of Coronel. With Turkey's entry into the conflict on 29 October, war also came to the British and Ottoman territories in the Middle East.

In Africa, the war's smallest military arena, Allied forces generally held the upper hand. In December 1914, South African troops crushed a domestic pro-German rebellion and, the following July, occupied German South-West Africa (present-day Namibia). Cameroon surrendered to Anglo-French troops in February 1916.

The most protracted battle took place in German East Africa, where troops under the command of General von Lettow-Vorbeck only surrendered two weeks after the final European armistice in late November 1918. By then, Germany's imperial ambitions in Africa lay in tatters.

In the Middle East, the contested inheritance of the Ottoman empire created a complex political and military situation. Britain, whose regional power centred on Egypt and the Suez Canal, coveted Turkey's Asiatic possessions. British generals and politicians also believed that the Middle East could provide the spectacular military victories - so absent from the fighting on the Western Front - that would galvanise pro-war public opinion at home.

Fears that Turkey's entrance into the war would spark a Muslim jihad ('holy war') in the region proved to be unfounded. With the exception of the Senussi revolt in Libya between 1915 and 1917, anti-Western Arab revolt was largely a chimera.

During the autumn and winter of 1916, British forces finally began to make progress, advancing across the Sinai desert and heading for Jerusalem, which was captured in December 1917. By October 1918, as the Turks made last-ditch overtures for peace, Britain was in full control of Palestine. But its problems in the region, laid bare by the contradictory promises to Arabs and Jews that dated from the Balfour declaration (2 November 1917), were only just beginning.

However, defeat at the Battle of Ctesiphon (22-26 November 1915) forced the heavily depleted British forces to retreat to Kut, where they endured a five-month siege in terrible conditions. More than 9,000 British troops trapped there finally surrendered to the Turks on 29 April 1916. With reinforced troop divisions and new leadership, however, British forces were able to retake Kut on 24 February 1917, and Baghdad was finally captured just a fortnight later. By 30 October 1918, when the war with Turkey ended, Britain was the supreme power in the Muslim world.