old usage of the Persians to regard the Sasanid kings, the descendants of the legendary kayani dynasty of heroes who had first established a settled community in Persia, as bagh not quite perhaps what we should understand as "gods," but rather as incarnations of deity, the divine spirit passing on by transmigration from one ruler to another, and so they ascribed to the king miraculous powers and worshipped him as the shrine of a divine presence. At the Muslim conquest the Sasanid kings had not only ceased to rule, but the dynasty had become extinct. Many of the Persians who, in spite of adopting Islam, still clung to their old ideas, were quite ready to treat the Khalif with the same adoration as their kings, but felt a distinct distaste for the theory of the Khalifate according to which the Khalif was no more than a chieftain elected in the democratic fashion of the desert tribes, a thing which seemed to them like reversion to primitive barbarism. Our own experience in dealing with oriental races has shown us that there is a great deal which must be taken seriously in ideas of this kind. Of course those who had been subjects of the Roman Empire had no inclination towards deifying their rulers, unless perhaps some who had been only recently incorporated from more oriental elements: but those who had been under Persian rule craved a deified prince. In A.H. 141–142 this took the form of an attempt to deify the Khalif by a fanatical sect of Persian origin known as the Rawandiyya which broke out into open revolt when the
