On 25 September 762, Muhammad declared himself at Medina, catching the Abbasid governor, Riyah ibn Uthman, by surprise. The rebellion was bloodless and Muhammad quickly gained the support of the old Muslim families of Medina and Mecca (the Ansar), but the movement had been doomed from the start: despite Medina's great symbolic value, it had little strategic importance, and the error of using it as the centre of a rebellion became apparent when the Abbasids immediately cut off the grain supply from Egypt that fed the city. Al-Mansur himself was relieved at the news of the uprising in such a remote location, remarking that at last he had "enticed the fox out of his hole".[1][2][3] Al-Mansur left Baghdad, whose construction he was supervising, for Kufa.