The most difficult task for us is to appreciate the strong appeal which the doctrines of incarnation and transmigration made to the Persian and Mesopotamian mind. Both these doctrines had figured prominently in pre-Islamic religions in Western Asia; and both recur in most religious movements from the coming of Islam to the present day in that particular area. We may note a few instances to illustrate this, and show incidentally the strong attraction these doctrines had for the Persian mind. Abu Muslim was the general who more than any other helped to seat the ʿAbbasids on the throne, and suffered death at the hands of the first ʿAbbasid Khalif, who was jealous,—with good cause, it would appear,—of his excessive power. But Abu Muslim had exercised an extraordinary influence over men during life, and was treated as a quasi-divine hero after death, his admirers regarding him as not really dead but as having passed into “concealment,” some other having been miraculously substituted for him at the moment of execution. This resembles the theory which the pre-Islamic Persian teacher Mani held as to Christ. Mani fully accepted Christ as a religious teacher, side by side with Zoroaster and Buddha, but he could not admit the reality of his death, for a material body capable of death was in his view unworthy of one purely good. He supposed, therefore, that at the crucifixion Simon of Cyrene was at the last moment substituted for Christ, and this Persian idea has actually obtained a place in the Qurʾan (cf. Sura 4, 156). Not long after Abu Muslim we hear of a pseudo-prophet named Bih-afaridh, a Zoroastrian who had travelled in the far East, and afterwards accepted Islam at the hands of two _duʿat_ who were preaching the cult of Abu Muslim. Very little is known of his teaching, but he certainly maintained the doctrine that the Imam is an incarnation of the Deity, and seems to have attached a particularly sacred signification to the numeral seven. This superstitious reverence for particular numbers was a common feature in the pre-Islamic religions of Mesopotamia, and we shall meet it again in the doctrines of the Ismaʿilians. Another sect, of similarly pre-Islamic origin, was that known as the _Rawandiyya_ from its origin at Rawand near Isfahan. Its members were king-worshippers in the old Persian sense, and a body of them travelled to Hashimiyya, where the Khalifs then had their residence, and tried to acclaim the Khalif al-Mansur as a god. He not only rejected the proffered adoration, but cast the leaders into prison. This was followed by an attempt to attack the palace, the Rawandis considering that, as the prince had disclaimed deity, he could be no valid ruler. For some centuries the sect, strongly disaffected towards the Khalifate, lingered on in Persia and had many sympathisers.