y ars , ▁who ▁formerly ▁had ▁been ▁loyal ▁v ass als ▁of ▁the ▁Kh az ars . ▁The ▁presence ▁of ▁Kab ar ▁political ▁refuge es ▁from ▁Kh az aria ▁among ▁the ▁Var ang ian ▁trad ers ▁in ▁Rost ov ▁helped ▁to ▁raise ▁the ▁latter ' s ▁prest ige , ▁with ▁the ▁consequence ▁that ▁by ▁the ▁ 8 3 0 s ▁a ▁new ▁power ▁center ▁known ▁as ▁the ▁Rus ' ▁K agan ate ▁had ▁come ▁into ▁existence ." ▁▁ ▁In ▁ 8 9 4 , ▁the ▁By z antine ▁em peror ▁Leo ▁VI , ▁then ▁at ▁war ▁with ▁S ime on , ▁the ▁Bulgar ian ▁cz ar ▁( 8 9 3 – 9 2 7 ), ▁called ▁the ▁Hung ari ans ▁to ▁his ▁aid . ▁The ▁Mag y ars , ▁led ▁by ▁Á rp ád , ▁crossed ▁the ▁Dan ube ▁and ▁attacked ▁Bulg aria . ▁The ▁Bulg ari ans , ▁in ▁turn , ▁appe aled ▁to ▁the ▁Pe chen eg s , ▁now ▁master s ▁of ▁the ▁ste ppe , ▁who ▁attacked ▁the ▁Hung ari ans ▁in ▁the ▁rear ▁Tow ard ▁ 8 5 0 ▁or ▁ 8 6 0 , ▁driven ▁from ▁Lev edia ▁by ▁the ▁Pe chen eg s , ▁they ▁entered ▁At el ku zu ▁( E tel kö z ) ▁taking ▁refuge ▁in ▁the ▁mountains ▁of ▁Trans ylvan ia . ▁At ▁that ▁moment , ▁Arn ulf , ▁du ke ▁of ▁Car inth ia , ▁at ▁war ▁with ▁the ▁S lav ▁r uler ▁S vat op l uk , ▁prince ▁of