Abbasid (Arabic: العبّاسيّون, al-‘Abbāsīyūn) is the dynastic name generally given to the caliph of Baghdad, the second of the two great Sunni Muslim caliphates of the Arab Empire, that overthrew the Umayyad caliphs from all but Al Andalus. It was built by the descendant of Muhammad's youngest uncle, Abbas ibn Abd al-Muttalib. It seized power in 750 and shifted the capital from Damascus to Baghdad. It flourished for two centuries, but slowly went into decline with the rise to power of the Turkish army it had created, the Mamluks. Within 150 years of gaining power across Persia, they were forced to cede power to local dynastic amirs who only nominally acknowledged their power, and had to cede Al Andalus to an escaped Umayyad royal and the Maghreb and Ifriqiya to independent entities such as the Aghlabids and the Fatimids. Their rule was ended in 1258, when Hulagu Khan, the Mongol conqueror, sacked Baghdad. While they continued to claim authority in religious matters from their base in Egypt, the dynasty's secular authority had ended. Descendants of the Abbasids include the al-Abbasi tribe who live northeast of Tikrit in modern-day Iraq.