The Abbasid Revolution ended what the narrative calls the “Arab kingdom” of the Umayyad period. Its success depended on dissatisfied groups, especially non-Arab Muslims who demanded a fuller share in a community founded on equality among believers. The new dynasty therefore presented Islam, rather than Arab identity, as the principal basis of political legitimacy.

A decisive symbolic and geographical transformation came in 762, when the Abbasids transferred the capital from Syria to Iraq and founded Baghdad. The move shifted the empire’s centre of gravity toward the eastern provinces and accompanied a stronger official emphasis on orthodox Islam. During the first century of Abbasid rule, the caliphate continued to expand, including the annexation of Caspian provinces and the beginning of the Aghlabid conquest of Sicily.

The Abbasid realm was smaller than the former Umayyad empire because Muslim Spain remained outside it. During the first fifty years, the dynasty also lost control of African provinces west of Egypt to Kharijites and the Idrisids, while the governor of Ifriqiya, al-Aghlab, became virtually independent in 800. Later, dissident movements and provincial dynasties accelerated fragmentation: the Buyids controlled Iraq and made the Abbasid caliphs their political puppets, while the Fatimids detached Egypt, Syria, and Arabia.