ABSTRACT
The rise of the 'Abbasid dynasty in 133/750 did not cause a sudden, total transformation in the order of society which had been created by the Umayyads. Rather, the 'Abbasid revolution was the emergence of a new political order as the culmination of gradual developments which had been taking place under the previous regime. The formation of those units attests to a particular characteristic of 'Abbasid policy. Like the Umayyads before them, the 'Abbasids took sides in the tribal factionalism between Qays and Yaman. The professional skills required by the clerks encouraged cooperation and espirit de corps, on the one hand, and nepotism and factionalism, on the other. Many of the leading bureaucratic families had been in government service for generations, and they tended to train their children to follow in their footsteps, which constituted a striking element of the continuity of bureaucratic personnel from the Umayyad to the 'Abbasid regime.
