From the sixteenth century until 1918, the area of what is now Iraq made up only a small part of the vast Ottoman Empire that extended from central Europe in the west, to the Persian border in the east. It also included most of the Arabian Peninsular and North Africa.

The territory that was to become Iraq was to be made from three distinct and separate Ottoman provinces (vilayets) with many diverse ethnic and tribal differences; predominantly Shi'ite Muslim Basra in the south, Baghdad in the middle and largely Sunni Muslim Mosul in the north. In the north and central west are a large minority of Kurds.

This unnatural union would prove difficult to hold together.