His outward appearance was strangely fascinating; he was a man of strong constitution, very dark complexion, and his face always wore a pleasant smile, to which he had by long practice accustomed himself. Under this smile gleamed a set of singularly white teeth, and between the two upper middle ones was a V-shaped space, which in the Sudan is considered a sign that the owner will be lucky. His mode of conversation too had by training become exceptionally pleasant and sweet. As a messenger of God, he pretended to be in direct communication with the Deity. All orders which he gave were supposed to have come to him by inspiration, and it became therefore a sin to refuse to obey them; disobedience to the Mahdi's orders was tantamount to resistance to the will of God, and was therefore punishable by death. He called himself Mahdi Khalifat er Rasul (_i.e._ the successor of the Prophet), while his adherents called him "Sayid" (_i.e._ Master); Sayidna el Mahdi (_i.e._ our Master the Mahdi), or Sayidna el Imam (_i.e._ our Master the head, or one who goes in front). The Mahdi in his every action endeavoured to imitate and follow in the exact footsteps of the Prophet. Thus he made his hejira or flight to Gedir, and there appointed his four Khalifas. The first of these was the Khalifa Abdullah, who assumed the title of Khalifa Abu Bakr, or Khalifa Es Sadik; he belonged to the Taisha section of the Baggara tribe, and it was through his influence that the Taisha, Rizighat and Homr Baggaras were won over to the Mahdi's cause. It was agreed that Khalifa Abdullah should, in the event of the Mahdi's death, succeed.