Historians differ very much as to how far the Fatimids succeeded in proving their ʿAlid descent, and contemporary opinion was quite as varied. Abu l-Hasan Muhammad Masawi, commonly known as Radi, born at Baghdad in 359 and dying in 406, was himself an undoubted descendant of Husayn the son of ʿAli, and was official keeper of the records of ʿAlid genealogy. As Abu l-Feda notes (_Ann. Mosl._, ii. 309) he, in one of his poems, fully admits the legitimate descent of the Fatimids of Egypt from ʿAli, and the actual passage is extant (cf. _Diwan_ of Radi, Beirut, p. 972): but in 402 this same Radi joined with other ʿAlids and certain canonists in a proclamation denouncing the Fatimids and declaring their claimed genealogy as baseless. It is natural to suppose that in this he was actuated by fear or complaisance, and this difficulty meets us throughout; the whole question was so much a matter of current political controversy that it was practically impossible to get anything like an unbiassed opinion. Maqrizi, the leading Egyptian authority of a later age, was strongly pro-Fatimid, but he claims the noble rank of _sayyid_ on the ground of descent from ʿAli through the Fatimids, and so is prejudiced in their favour. He argues that the ʿAlid descent of the Fatimids was never attacked by the acknowledged ʿAlids who then existed in considerable numbers (Maq. i., 349), an argument which is far from being true. Elsewhere Maqrizi defends the Fatimid claims by saying that the ʿAlids were always suspected by the ʿAbbasid Khalifs, and so “they had no resort but to conceal themselves and were scarcely known, so that Muhammad b. Ismaʿil, the Imam ancestor of ʿUbayd Allah, was called the ‘concealed’” (Maq. i., 349). But this tells the other way: it admits that the ʿAlid genealogy was not well known: and the mere fact that ʿAbdullah was sought for by the Khalif simply shows that his pretensions were known to be dangerous, as a Mahdi with a body of followers would necessarily be, and is no proof of the validity of the descent afterwards claimed by ʿAbdullah’s descendants. The obscurity of the ʿAlid genealogy afterwards favoured the Fatimid claims, but it does not seem that that claim was part of their original programme. The first idea was to support the claims of the vanished Imam, claims selected in all probability because of the convenient fact that he had vanished, and to represent ʿAbdullah and his descendants simply as Mahdis, viceroys to guide and direct the people of Islam until the day came for the concealed Imam to be revealed again.