There was none which did not strive to become, in the strictest sense, predominant, and to seat the princes of their faith on the throne of Islam. Their missionaries (Dai) claimed not only the faith, but also the obedience of the people, and were at once apostles and pretenders. All the heresies, which we have hitherto mentioned, were, in spirit, essentially usurping sects. Islamism, however, bore in its bosom others still more prejudicial to its existence; sects, which trampling under foot all the maxims of faith and morality, and preaching the overthrow of thrones and altars, bore as their cognizance, equality and liberty. We have still to give some details concerning these latter; to which, in order to distinguish them from the former, to whom they are entirely opposed, we shall give the name of revolutionary. The Persian empire, the most ancient and likewise the best regulated monarchy of the east, was the first to experience, and had, for the longest period endured, all the horrors of despotism and anarchy arising from unbounded power and resisting liberty. As long as the faith of Zoroaster preserved its primeval purity, and the sacred fire still burned in the temples, religion could neither afford a shield nor a mask to rebellion; but when, under the Sassanides, the edifice of the ancient system was shaken by new opinions and reforms, the temple and the palace began alike to totter. Innovators and heretics sprung up, and sedition undermined, at the same moment, both the altar and the throne.