sent to the Yemeni faithful, documenting his supposed genealogy. This letter caused much unease and dissension, for al-Mahdi claimed descent from Ja'far al-Sadiq, the last common imam recognized by Twelvers and Isma'ilis alike, via al-Sadiq's eldest son Abdallah al-Aftah, whom he named as the father of his own great-grandfather, Abdallah al-Akbar. Not only did this contradict all previous Isma'ili propaganda, which emphasized that the legitimate imamate had followed the line of al-Sadiq's younger son Isma'il, but the claimed genealogy was patently false: Abdallah al-Aftah died young, and was commonly known to not have had any offspring. The same letter further upended previous doctrine by emphasizing that though he was the expected , his rule would not bring about the end times, but merely represent another link in a line of imams that was to continue endlessly into the future, thereby contradicting all millennialist expectations vested in his person. The other Isma'ili in the Yemen, Ibn Hawshab, remaine dloyal to al-Mahdi, but was forced to capitulate against Ibn al-Fadl's forces, and hand over his son Ja'far as a hostage. Both s died withi a few months of each other in 915—Ibn al-Fadl was said to have been poisoned by agents of al-Mahdi posing as physicians—leading to the swift collapse of Isma'ili rule in the Yemen. By 917 the Sunni Yu'firids had completed the reconquest of the country in the name of the Abbasid caliph. First invasion of Egypt The first expedition against Egypt was launched on 24 January 914, led by Habasa ibn Yusuf. Advancing along the coast, on 6 February it entered Barqa, the capital of Cyrenaica. There Habasa executed two chieftains of the Mazata tribe, who nine years before had waylaid and robbed al-Mahdi during his journey to Ifriqiya; their sons were also killed, and their womenfolk sold into slavery and their possessions confiscated. Encouraged by this success, on 11 July al-Mahdi sent al-Qa'im with another army east to assume command of the expedition. Disregarding these orders, however, the ambitious Habasa led his forces into Egypt, entering Alexandria on 27 August. The news of the Fatimid invasion threw Baghdad into a panic. The Abbasid government had paid little attention to the affairs of Ifriqiya and the claims of al-Mahdi, but now urgent inquiries were made as to his origin and intentions. The Fatimid campaign in Egypt ultimately failed. The attempts to cross the Nile at Giza and capture Fustat