Ali ibn al-Fadl al-Jayshani

ʿAlī ibn al-Faḍl al-Jayshānī (Arabic: علي بن الفضل الجيشاني) was a senior Isma'ili missionary (dāʿī) from Yemen. In cooperation with Ibn Hawshab, he established the Isma'ili creed in his home country and conquered much of it in the 890s and 900s in the name of the hidden Isma'ili imam, Abdallah al-Mahdi Billah. After the establishment of the Fatimid Caliphate in Ifriqiya in 909, and the public proclamation of al-Mahdi Billah as caliph, Ibn al-Fadl denounced al-Mahdi as false, and instead declared himself to be the awaited messiah (mahdī). His erstwhile colleague, Ibn Hawshab, refused to follow him, so Ibn al-Fadl turned against him and forced him to capitulate. Ibn al-Fadl's dominion collapsed swiftly after his death in October 915. In January 917, his stronghold of Mudhaykhira was seized by the Yu'firids, his children captured, and his two sons executed.