East and West, in accordance with God's promise, from sinful rebels". However, in those universalist claims lay the very problem of the new regime; as the historian Hugh Kennedy writes, "the moment when a revolutionary movement achieves power is always of crucial importance", since it has to fulfill its promises to its followers. Al-Mahdi had come to power riding a wave of millennialist and messianic promises, his followers expecting a divinely inspired leader capable of performing miracles. Once in power, however, he would prove to be a mere mortal, and focused more on his legitimist claim on the caliphate as a descendant of Ali, rather than attempting to fulfill the overblown expectations placed on the ' of God' that Abu Abdallah had heralded. The way that al-Mahdi subtly managed expectations can be seen in the choice of his regnal name: 'Abdallah Abu Muhammad' was the exact reverse of the name of the Islamic prophet Muhammad, and also ensured that his son, now known as Abu'l-Qasim Muhammad rather than Abd al-Rahman, would bear the same name as the Islamic prophet, as had long been prophesied for the : Abu'l-Qasim Muhammad ibn Abdallah. As Halm points out, this allowed al-Mahdi to shift the millennialist expectations onto his son, buying time. At the same time, however, this also meant that the singular, semi-divine figure of the was now reduced to an adjective in a caliphal title, 'the Imam rightly guided by God' (): instead of the promised messiah, al-Mahdi was merely one in a long sequence of imams descending from Ali and Fatima. A major problem faced by al-Mahdi was the narrow basis of the new regime. The Fatimid dynasty was brought to power by the Kutama, who were thus "indispensable", but also "a liability and a threat" to its survival. Halm has described the early Fatimid regime as being little more than a "hegemony of the Kutama". The position of these semi-civilized tribesmen as the chosen warriors of the imam-caliph was greatly resented, not only by the other Berber tribes, but chiefly by the inhabitants of the cities, where the Arabic culture predominated. As Halm writes, the situation was similar to a scenario where, "in the early eighteenth-century North America, the Iroquois, converted to Catholicism by Jesuit missionaries, had overrun the Puritan provinces of New England, installed their chieftains as governors in Boston, Providence and Hartford, and proclaimed a European with dubious