 In the early seventh century Heraclius the Elder, the exarch of Carthage, overthrew the Byzantine emperor Phocas, whereupon his son Heraclius succeeded to the imperial throne.The Roman Exarchate of Africa was not able to withstand the seventh-century Muslim conquest of the Maghreb.The Umayyad Caliphate under Abd al-Malik ibn Marwan in 686 sent a force led by Zuhayr ibn Qays, who won a battle over the Romans and Berbers led by King Kusaila of the Kingdom of Altava on the plain of Kairouan, but he could not follow that up.