ā n ▁( ), ▁often ▁referred ▁to ▁simply ▁as ▁Q ays ▁( K ais ▁or ▁ <0xE1> <0xB8> <0xB2> ays ) ▁were ▁an ▁Arab ▁trib al ▁conf eder ation ▁that ▁branch ed ▁from ▁the ▁M ud har ▁section ▁of ▁the ▁Ad nan ites . ▁The ▁tribe ▁does ▁not ▁appear ▁to ▁have ▁function ed ▁as ▁a ▁unit ▁in ▁the ▁pre - I sl am ic ▁era . ▁However , ▁by ▁the ▁early ▁Um ay y ad , ▁its ▁constitu ent ▁tribes ▁cons olid ated ▁into ▁one ▁of ▁the ▁main ▁tri bo - polit ical ▁fa ctions ▁of ▁the ▁cal i ph ate . ▁ ▁The ▁major ▁constitu ent ▁tribes ▁or ▁trib al ▁group ings ▁of ▁the ▁Q ays ▁were ▁the ▁Haw az in , ▁Ban u ▁' Am ir , ▁Ban u ▁Th a q if , ▁Ban u ▁Sul ay m , ▁Ban u ▁Gh ani , ▁Bah ila ▁and ▁Ban u ▁Mu har ib . ▁Many ▁of ▁these ▁tribes ▁or ▁their ▁cl ans ▁migr ated ▁from ▁the ▁Arab ian ▁Pen ins ula ▁and ▁established ▁themselves ▁in ▁northern ▁Sy ria ▁and ▁Upper ▁Mes op ot am ia , ▁which ▁long ▁became ▁their ▁ab ode . ▁From ▁there ▁they ▁govern ed ▁on ▁beh alf ▁of ▁the ▁cal i ph s ▁or ▁re bel led ▁against ▁them . ▁The ▁power ▁of ▁the ▁Q ays ▁as ▁a ▁un ified ▁group ▁dimin ished ▁with ▁the ▁rise ▁of ▁the ▁Abb as id ▁C ali ph ate ▁which ▁did ▁not ▁derive ▁its ▁military ▁strength ▁sole ly ▁from ▁the ▁Arab