3 0 . ▁Mar wan ▁ibn ▁Muhammad , ▁the ▁future ▁Mar wan ▁II , ▁finally ▁ended ▁the ▁war ▁in ▁ 7 3 7 ▁with ▁a ▁massive ▁invasion ▁that ▁is ▁reported ▁to ▁have ▁reached ▁as ▁far ▁as ▁the ▁Vol ga , ▁but ▁the ▁Kh az ars ▁remained ▁un sub du ed . ▁ ▁H ish am ▁suffered ▁still ▁worse ▁defe ats ▁in ▁the ▁east , ▁where ▁his ▁arm ies ▁attempted ▁to ▁sub due ▁both ▁Tok har istan , ▁with ▁its ▁center ▁at ▁B alk h , ▁and ▁Trans ox iana , ▁with ▁its ▁center ▁at ▁Sam ark and . ▁Both ▁areas ▁had ▁already ▁been ▁partially ▁conquer ed , ▁but ▁remained ▁difficult ▁to ▁govern . ▁Once ▁again , ▁a ▁particular ▁difficulty ▁concerned ▁the ▁question ▁of ▁the ▁conversion ▁of ▁non - A rab s , ▁especially ▁the ▁S og d ians ▁of ▁Trans ox iana . ▁Following ▁the ▁Um ay y ad ▁defeat ▁in ▁the ▁" Day ▁of ▁Th irst " ▁in ▁ 7 2 4 , ▁Ash ras ▁ibn ▁' Ab d ▁Al lah ▁al - S ul ami , ▁governor ▁of ▁Kh uras an , ▁promised ▁tax ▁relief ▁to ▁those ▁S og d ians ▁who ▁converted ▁to ▁Islam , ▁but ▁went ▁back ▁on ▁his ▁offer ▁when ▁it ▁proved ▁too ▁popular ▁and ▁threatened ▁to ▁reduce ▁tax ▁reven ues . ▁ ▁Dis content ▁among ▁the ▁K hor as ani ▁Arab s ▁rose ▁sharp ly ▁after ▁the ▁losses ▁suffered ▁in ▁the ▁Battle ▁of ▁the ▁De file ▁in ▁ 7 3 1 . ▁In ▁ 7 3 4