Abdullah ibn-Mohammed al-Khalifa or Abdullah al-Khalifa or Abdallahi al-Khalifa, also known as "The Khalifa" was a Sudanese Ansar ruler who was one of the principal followers of Muhammad Ahmad. Ahmad claimed to be the Mahdi, building up a large following. After Ahmad's death, Abdullah ibn-Mohammed took over the movement, adopting the title of Khalifah al-Mahdi. He attempted to create a kingdom, which led to widespread discontent, and his eventual defeat and death at the hands of the British and Egyptians.
Artistic representation of Abdallahi ibn Muhammad
A depiction of the Khalifa inciting his troops to attack Kassala, from Rudolf Carl von Slatin's Fire and Sword in the Sudan (1896)
The body of the Khalifa (third from the right) on the battlefield of Umm Diwaykarat
The Ansar are a Sufi religious movement in the Sudan whose followers are disciples of Muhammad Ahmad, a Sudanese religious leader based on Aba Island who proclaimed himself Mahdi on 29 June 1881. His followers won a series of victories against the Egyptians, culminating in the capture of Khartoum in January 1885.
Muhammad Ahmad, who inspired the Ansar movement
A Mahdist Dervish from Sudan (1899)