Mesopotamia is the land which lies between the rivers Euphrates and Tigres in the Middle East. The area was devastated by the Mongols in the 15th century and eventually became part of the Turkish Ottoman Empire.

In the summer of 1914 the British government suspected an imminent war with Turkey and took measures to protect oil supplies from Abadan. The Indian Army and the Royal Navy's Gulf Division, were placed at the mouth of the Shatt-al-Arab and when war was declared on 5th November, they moved forward and took the port of Basra. By early December, Qurna, upriver at the junction of the Tigres and Euphrates was also under British control.

The Assyrian Levie forces played a very important role in the conflict with Turkey. It is estimated that around two-thirds of the Assyrian population lost their lives during the First World War.

In 1920 the League of Nations granted Britain a mandate to control the area. Britain provided Iraq with a constitution and arranged for Faisal I, the son of Sharif Husain of Mecca, to become king of Iraq. The Kurds were unhappy with this arrangement and were involved in several uprisings against British rule.