If proof were needed that the foundations of the ʿAbbāsid regime, as laid down by Manṣūr, were not as strong as they seemed, it was not long in coming. Hardly a generation after his death the empire was once more embroiled in a devastating civil war that explicitly pointed up the weaknesses of the regime. Over a period of thirty-five years three ʿAbbāsid rulers followed the political orthodoxy of their founding-father without much deviation. Although some changes occurred, these were, on the whole, ad hoc measures which were attempted only as situations arose that threatened the central control. The general policy line was to enhance the power of the ruler and his central government, and that was thought to be enough to govern his vast empire. Changes in taxation were introduced to enrich the treasury without much regard to the interests of the tax-payers. Modifications in the administration were attempted for the sole purpose of tightening the grip of Baghdād over the provinces. The rulers persisted in assuming titles with religious connotations in the hope that this would give them some semblance of religious authority. They continued to use the Khurāsāniyya, their force de frappe, to counter the protestations of any dissident subjects. However, they failed to see that such a militia did not constitute a professional standing army or that it was no substitute for one.