Persia is the region in which resistance comes to a head against the caliphate of the Umayyads in Damascus. The uprising is partly a simple struggle between Arab factions, each of impeccable pedigree in relation to the pioneers of Islam. A revolt in Persia in 747 is headed by descendants of al-Abbas, an uncle of the prophet Muhammad. Their new caliphate, established in 750, will be known as Abbasid.
The involvement of Persia is also significant. The Umayyad caliphate in Damascus derives from the early days of Islam when all Muslims are Arabs. But many Muslims in the east are now Persian, and Persian sophistication is beginning to divert Muslim culture from its simple Arab origins.
Abbasid forces reach and capture Damascus in 750. Abul Abbas is proclaimed the first caliph of a new line. Male members of the Umayyad family are hunted down and killed (though one survives to establish a new Umayyad dynasty in Spain).
The centre of gravity of the Muslim world now moves east, from Syria to Mesopotamia. In 762 a new capital city, Baghdad, is founded on the Tigris. It is about twenty miles upstream from Ctesiphon, one of the leading cities of the preceding Persian dynasty, the Sassanians.
Baghdad: 8th century
In their new city of Baghdad the Abbasid caliphs adopt the administrative system of the long-established Persian empire. Persian Muslims are as much involved in the life of this thriving place as Arab Muslims. Here Islam outgrows its Arab roots and becomes an international religion. Here the Arabic and early Persian languages coalesce to become, from the 10th century, what is now known as Persian – combining words from both sources and using the Arabic script. Here Mesopotamia briefly recovers its ancient status at the centre of one of the world’s largest empires.