▁He ▁quickly ▁occupied ▁the ▁western ▁B alk an ▁lands ▁from ▁Bel grade ▁to ▁Lar issa ▁but ▁in ▁the ▁next ▁year ▁he ▁was ▁bet rayed ▁by ▁his ▁cousin ▁Al us ian , ▁who ▁blind ed ▁him ▁with ▁a ▁kn ife ▁after ▁he ▁got ▁dr unk ▁during ▁a ▁fe ast . ▁Though ▁blind , ▁Peter ▁D ely an ▁remained ▁in ▁command ▁and ▁met ▁the ▁By z ant ines ▁near ▁Ost ro vo . ▁The ▁battle ▁itself ▁is ▁unclear ▁but ▁the ▁Bulg ari ans ▁were ▁defeated ▁mainly ▁with ▁the ▁help ▁of ▁the ▁Var ang ian ▁Guard , ▁led ▁by ▁Har ald ▁Hard r ada . ▁D ely an ▁was ▁captured ▁and ▁was ▁sent ▁to ▁Th ess al on iki . ▁Al us ian , ▁who ▁initially ▁sought ▁to ▁lead ▁the ▁army ▁against ▁the ▁By z ant ines , ▁secret ly ▁negoti ated ▁a ▁deal ▁with ▁Emperor ▁Michael ▁IV ▁at ▁Mos yn opol is ▁and ▁was ▁reward ed ▁with ▁a ▁title ▁of ▁mag ist ros . ▁During ▁the ▁battle , ▁he ▁rode ▁to ▁the ▁safety ▁of ▁enemy ▁lines , ▁leaving ▁the ▁Bulgar ian ▁army ▁to ▁be ▁cr ushed . ▁As ▁a ▁result , ▁the ▁u pr ising ▁was ▁rep uls ed ▁and ▁the ▁em peror ▁entered ▁Bulg aria , ▁which ▁remained ▁a ▁By z antine ▁province ▁until ▁ 1 1 8 5 . ▁ ▁References ▁ ▁Category : 1 0 4 1 ▁in ▁Europe ▁Category : 1 0 4 0 s ▁in ▁the ▁By z antine ▁Empire ▁Ost ro vo ▁Ost ro vo ▁Ost ro vo ▁Category