The Mahdist War was a war between the Mahdist Sudanese, led by Muhammad Ahmad bin Abdullah, who had proclaimed himself the "Mahdi" of Islam, and the forces of the Khedivate of Egypt, initially, and later the forces of Britain. Eighteen years of war resulted in the creation of Anglo-Egyptian Sudan (1899–1956), a de jure condominium of the British Empire and the Kingdom of Egypt in which Britain had de facto control over Sudan. The Sudanese launched several unsuccessful invasions of their neighbours, expanding the scale of the conflict to include not only Britain and Egypt but also the Italian Empire, the Congo Free State and the Ethiopian Empire.

Muhammad Ahmad bin Abdullah bin Fahal was a Sudanese religious and political leader. In 1881, he claimed to be the Mahdi, and led a war against Ottoman-Egyptian rule in Sudan which culminated in a remarkable victory over the British in the Siege of Khartoum, while also slowing and defeating the British during their unsuccessful Nile Expedition to resupply the Khartoum Garrison. He created a vast Islamic state extending from the Red Sea to Central Africa, and founded a movement that remained influential in Sudan a century later.