Ismaîlis, 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.