A military force from this empire stopped Tang expansion under Emperor Xuan
A military force from this empire stopped Tang expansion under Emperor Xuangzong at the Battle of Talas, though mercenaries from this empire were sent to aid the Tang during the An Shi revolt. This empire formed following a victory at the Battle of Zab, and one ruler from it sent an elephant to Charlemagne. This empire's capital was sacked by Hulagu Khan, after which it relocated to Egypt and fractured into several factions such as the Fatimids and Almohads. Its most famous ruler, Harun-al-Rashid, established a House of Wisdom. For 10 points, identify this dynasty that succeeded the Umayyads with a capital in Baghdad.
A military force from this empire stopped Tang expansion under Emperor Xuangzong at the Battle of Talas, though mercenaries from this empire were sent to aid the Tang during the An Shi revolt.
{Abbasid} Caliphate