It is not too much to describe the Ṣaffārids of S‚stān as an archetypal military dynasty. In the later years of the third/ninth century, their empire covered the greater part of the non-Arab eastern Islamic world. In the west, Ya'qūb. al-Laith's army was only halted at Dair al-'Āqūl, 50 miles from Baghdad; in the north, Ya'qūb and his brother 'Arm campaigned in the Caspian coastlands against the local 'Alids, and 'Amr made serious attempts to extend his power into Khwārazm and Transoxania; in the east, the two brothers pushed forward the frontiers of the Dār al-Islām into the pagan borderlands of what are now eastern Afghanistan and the North-West Frontier region of West Pakistan; and in the south, Ṣaffārid authority was acknowledged even across the persion Gulf in ‘Umān. This impressive achievement was the work of two soldiers of genius, Ya'qūub and 'Amr, and lasted for little more than a quarter of a century. It began to crumble when in 287/900 the Sāmānid Amīr Ismā'īl b. Aḥmad defeated arid captured ‘Amr b. al-Laith, and 11 years later, the core of the empire, Sīstān itself, was in Sāmānid hands. Yet such was the effect in Sīstān of the Ṣaffārid brothers’ achievement, and the stimulus to local pride and feeling which resulted from it, that the Ṣaffārids returned to power there in a very short time. For several more centuries they endured and survived successive waves of invaders of Sīstān—the Ghaznavids, the Seljūqs, the Mongols—and persisted down to the establishment of the Ṣafavid state in Persia.