أحمد بن طولون
As the situation in the capital declined, various groups in different parts of the empire took advantage of this period of weakness. In Tabaristan a Zaydi dynasty came to power in 864. In 868 the Turk Ahmad ibn Tulun gained control of Egypt and gradually asserted his independence from Samarra. In Lower Iraq and Khuzistan, the Zanj Rebellion began in 869 and posed a serious threat to the Abbasid Caliphate in the region.