▁Ah na f ▁ibn ▁Q ais ▁and ▁Abd ul lah ▁ibn ▁A am ir . ▁Abd ul lah ▁march ed ▁from ▁F ars ▁and ▁took ▁a ▁short ▁and ▁less ▁frequent ▁route ▁via ▁Ray y . ▁Ah na f ▁then ▁march ed ▁north ▁direct ▁to ▁Mer v , ▁in ▁present ▁Turk men istan . ▁Mer v ▁was ▁the ▁capital ▁of ▁Kh uras an ▁and ▁here ▁Y az de ger d ▁III ▁held ▁his ▁court . ▁On ▁hearing ▁of ▁the ▁Muslim ▁advance , ▁Y az de ger d ▁III ▁left ▁for ▁B alk h . ▁No ▁resistance ▁was ▁offered ▁at ▁Mer v , ▁and ▁the ▁Muslim s ▁occupied ▁the ▁capital ▁of ▁Kh uras an ▁without ▁a ▁fight . ▁ ▁Second ▁phase ▁of ▁con quest ▁ ▁Far ru kh z ad , ▁the ▁previously ▁minister ▁of ▁Y az de ger d , ▁and ▁r uler ▁of ▁Tab ar istan , ▁managed ▁to ▁rep el ▁the ▁Arab s ▁with ▁the ▁aid ▁of ▁Gil ▁G av bara ▁and ▁make ▁a ▁treat y ▁with ▁them . ▁The ▁Arab s ▁then ▁inv aded ▁K hor as an , ▁and ▁made ▁a ▁treat y ▁with ▁the ▁kan ar ang ▁of ▁T us , ▁Kan ad b ak . ▁In ▁the ▁treat y ▁Kan ad b ak ▁agreed ▁to ▁surrender ▁and ▁assist ▁Muslim ▁forces ▁while ▁still ▁remaining ▁in ▁control ▁of ▁his ▁territ ories ▁in ▁T us . ▁Abd ul lah ▁and ▁Kan ad b ak ▁then ▁conquer ed ▁N ish ap ur ▁after ▁defeated ▁Kan ā r ang ī y ā n