▁an ▁important ▁part ▁in ▁the ▁Muslim ▁con quest s ▁of ▁Pers ia ▁under ▁al - M uth anna ▁al - Sh ay ban i ▁and ▁the ▁Lev ant . ▁During ▁C ali ph ▁U th man ' s ▁reign ▁( 6 4 4 – 6 5 6 ), ▁the ▁Muslim ▁governor ▁of ▁Sy ria , ▁Mu ' aw iy ah ▁I , ▁brought ▁numerous ▁Q ays i ▁tribes men ▁from ▁the ▁Ban u ▁Kil ab , ▁Ban u ▁U q ay l ▁( both ▁sub - t rib es ▁of ▁the ▁Ban u ▁' Am ir ) ▁and ▁the ▁Sul ay m ▁to ▁inhab it ▁Upper ▁Mes op ot am ia , ▁northern ▁Sy ria ▁and ▁the ▁front ier ▁region ▁with ▁the ▁By z antine ▁Empire ▁and ▁Armen ia . ▁Q ays i ▁tribes men ▁largely ▁fought ▁on ▁the ▁side ▁of ▁Ali ▁against ▁Mu ' aw iy ah ▁in ▁the ▁Battle ▁of ▁the ▁Cam el ▁and ▁the ▁Battle ▁of ▁S iff in ▁in ▁ 6 5 6 ▁and ▁ 6 5 7 , ▁respectively . ▁ ▁Um ay y ad ▁era ▁ ▁Mu ' aw iy ah ▁I ▁founded ▁the ▁Um ay y ad ▁C ali ph ate ▁in ▁ 6 6 1 . ▁Between ▁then ▁and ▁the ▁Um ay y ads ' ▁collapse ▁in ▁ 7 5 0 , ▁the ▁Q ays ▁formed ▁one ▁of ▁the ▁main ▁political ▁and ▁military ▁components ▁of ▁the ▁C ali ph ate . ▁Their ▁main ▁ant agon ist ▁were ▁the ▁Yam ani ▁tribes , ▁led ▁by ▁the