▁summer ▁of ▁ 1 1 3 6 , ▁Eric ▁under to ok ▁a ▁cr us ade ▁against ▁the ▁pag an ▁population ▁on ▁the ▁Balt ic ▁island ▁of ▁R ü gen ▁and ▁its ▁capital ▁Ark ona . ▁He ▁ordered ▁his ▁men ▁to ▁dig ▁a ▁canal ▁between ▁the ▁city ▁and ▁the ▁rest ▁of ▁the ▁island . ▁The ▁canal ▁had ▁the ▁effect ▁of ▁dry ing ▁up ▁the ▁spring ▁which ▁supplied ▁Ark ona ▁with ▁drink ing ▁water . ▁Ark ona ▁was ▁forced ▁to ▁surrender . ▁But ▁in ▁ 1 1 3 5 , ▁before ▁this ▁success ▁in ▁Ark ona , ▁Eric ▁defeated ▁in ▁a ▁naval ▁battle ▁near ▁Den mark ' s ▁coast ▁the ▁le ch it ic ▁( west - s lav ic ) ▁troops ▁under ▁pom er an ian ▁Duke ▁Rat ib or ▁who ▁had ▁s ack ed ▁Ros k ilde , ▁and ▁a ▁year ▁later , ▁after ▁the ▁battle ▁of ▁Kon ung ah ela , ▁( now ▁K ung äl v ▁in ▁Sweden ), ▁s ack ed ▁this ▁city ▁as ▁well . ▁He ▁joined ▁Magn us ▁for ▁an ▁un success ful ▁campaign ▁in ▁Norway , ▁where ▁he ▁managed ▁to ▁burn ▁down ▁Os lo . ▁When ▁he ▁learned ▁that ▁E sk il ▁had ▁raised ▁the ▁nobles ▁of ▁Zealand ▁against ▁him , ▁Eric ▁rac ed ▁north ▁to ▁put ▁down ▁the ▁re bell ion ▁which ▁spread ▁rapidly ▁across ▁Fun en ▁and ▁J ut land , ▁and ▁f ined ▁E sk il ▁heavily . ▁ ▁Death ▁Eric ▁was ▁killed ▁on ▁ 1 8 ▁September ▁ 1 1 3 7