 These competing influences gave birth to the Dervish State, a polity established by the religious leader Sayyid Mohammed Abdullah Hassan ("The Mad Mullah").The Dervish forces successfully repulsed the British Empire in four military expeditions and forced it to retreat to the coastal region, remaining independent throughout World War I.After a quarter of a century of holding the British at bay, the Dervishes were finally defeated in 1920, when Britain for the first time in Africa used airplanes to bomb the Dervish capital of Taleh.