Such was the system formed by ʿAbdullah, probably somewhere before A.H. 250, and by him grafted on the already existing sect of Shiʿites, which upheld the claims of Ismaʿil, the son of Jaʿfar. In the reign of Maʾmun (A.H. 198-218) ʿAbdullah had joined the revolt of Ishaq b. Ibrahim at Karkh and Ispahan, and formed a close friendship with the wealthy Muhammad b. Husayn b. Jihan-Bakhtar ad-Didan, a Persian prominent for his intense hatred of the Arabs, and it was he who first supplied ʿAbdullah with funds to begin his propaganda (cf. Quatremère in _Journ. Asiat._, Aug., 1836). It is not easy to form any clear scheme of the chronology of the sect in its early days, nor to follow the details of its history: conspiracies and secret societies do not leave much in the way of documentary evidence of their first formation. That ʿAbdullah was associated with a rebellion in the reign of Maʾmun is hardly likely; it seems rather that Muhammad b. Husayn ad-Didan (Dandan, or Zaydan) was so associated, and he afterwards befriended ʿAbdullah. This Muhammad was secretary to Ahmad ibn ʿAbdu l-ʿAziz ibn Abi Dolaf, who became prince of Karaj in A.H. 265. No doubt ʿAbdullah was a younger contemporary, assisted by the old anti-Arab agitator. Certainly ʿAbdullah was established at Basra, whither he had removed from Persia, before 261 (_Fihrist_, 187), lodging there with the family of ʿAgil ibn Abi Talib. Thence he went to Syria, presumably finding suspicion aroused at Basra, and made his headquarters at Salamiya in the territory of Emessa (Maq. i., 348-9: ii., 11), and from there sent out missionaries who preached the claims of Muhammad b. Ismaʿil b. Jaʿfar as the “concealed” Imam, and of ʿAbdullah himself as the Mahdi or “guide,” who was to prepare men for the Imam’s return to earth (Maq. i., 348). At Salamiya he had a son named Ahmad, and when he died Ahmad succeeded him as head of the sect. Ahmad, like his father, sent out missionaries, and one of these was instrumental in founding the important branch known as the _Qarmatians_, a branch so important and prominent that some, e.g., Jamal ad-Din, have regarded the Ismaʿilians as their off-shoot. The fact seems to be that there were at first members of one body, then circumstances gave the Qarmatians a political opening in Syria and ʿIraq, and, in a position of independence, they developed their doctrines more openly than the rest of the sect and, being drawn from the peasant class, these assumed a grosser form: whilst the other or parent community found a career in Africa but, as they became there a ruling minority with a subject majority of orthodox type, they were induced to observe some semblance of orthodoxy.