▁which ▁al - Z ub ay r ▁and ▁Tal ha ▁were ▁s lain ▁and ▁A ' ish a ▁consequ ently ▁entered ▁self - im posed ▁se clusion . ▁Ali ' s ▁so vere ig nt y ▁was ▁there after ▁recognized ▁in ▁Bas ra ▁and ▁Egypt ▁and ▁he ▁established ▁K uf a ▁as ▁the ▁C ali ph ate ' s ▁new ▁capital . ▁ ▁Although ▁Ali ▁was ▁able ▁to ▁replace ▁U th man ' s ▁govern ors ▁in ▁Egypt ▁and ▁Ira q ▁with ▁relative ▁ease , ▁Mu ' aw i ya ▁had ▁developed ▁a ▁solid ▁power - base ▁and ▁an ▁effective ▁military ▁against ▁the ▁By z ant ines ▁from ▁the ▁Arab ▁tribes ▁of ▁Sy ria , ▁which ▁he ▁govern ed ▁since ▁U mar ' s ▁reign . ▁Mu ' aw i ya ▁did ▁not ▁claim ▁the ▁cal i ph ate , ▁but ▁was ▁determined ▁to ▁retain ▁control ▁of ▁Sy ria ▁and ▁opposed ▁Ali ▁in ▁the ▁name ▁of ▁a ven ging ▁his ▁k ins man ▁U th man , ▁acc using ▁the ▁cal i ph ▁of ▁cul p ability ▁in ▁his ▁death . ▁Ali ▁and ▁Mu ' aw i ya ▁fought ▁to ▁a ▁st alem ate ▁at ▁the ▁Battle ▁of ▁S iff in ▁in ▁early ▁ 6 5 7 . ▁Ali ▁agreed ▁to ▁sett le ▁the ▁matter ▁with ▁Mu ' aw i ya ▁by ▁arbitr ation , ▁though ▁the ▁tal ks ▁failed ▁to ▁achieve ▁a ▁resolution . ▁The ▁decision ▁to ▁arbitr ate ▁fund ament ally ▁weak ened ▁Ali ' s ▁political ▁position ▁as ▁he ▁was