Theodor Nöldeke,
Sketches from Eastern History
“ The family of Táhir also, which from the days of Caliph Mámún had held the governorship of Khorásán, and of Sístán, which was regarded as an appendage, was unable to put down the Kharijites here, who steadily became more unruly as the power of the Táhirids waned. But in Sístán, as in other desert lands, Kharijite was often little more than a polite name for bandit. We thus understand how it was that, in the midst of this vigorous population, as the power of the State dwindled, volunteer bands were formed for defence against the Kharijites. ”
