One of the Mohammedan sects which support the claim of the house of Ali, Mahomet's cousin, to supremacy among the faithful; originating about A.D. 770, they rose to importance in the 10th century under Abdallah, a Persian, who introduced Zoroastrian ideas into their creed and prophesied the appearance of a Madhi or Messiah who should be greater than the Prophet himself; becoming latterly extremely rationalistic the sect lost its influence in the 13th century, and its representatives in Syria and Persia are now comparatively obscure; in Turkey and Egypt, however, several Madhis have arisen, of whom the last, Mohammed Ahmed, b . 1843, gained possession of the Soudan, defeated the Egyptian army in 1883, two years later captured Khartoum, but died at Omdurman shortly afterwards.