As "rulers by usurpation" (ʿalā sabīl al-taghallub), Isa and his son Ahmad are judged harshly by contemporary Muslim historians, but according to Canard, "in the disturbed period in which these Mesopotamian Arabs lived, they were no worse in their behaviour than the other soldiers of fortune of the Abbasid regime".[1] Canard credits Isa in particular with a "certain reputation for magnificence and generosity",[13] and like all the Shayban, Isa and Ahmad too were esteemed for the quality of their Arabic poetry.[15]