aedh mac cathal was murdered by the normans in 1228 and aedh mac ruaidri ua conchobair was chosen by the normans and the chiefs of connacht to take his place. yet in 1230 aedh and his vassals turned on the normans, vowing ""they would never own a lord who should bring them to make submission to the galls. they made then great raids on the galls, aed son of ruaidri and the men of west connacht plundering the young son of william and adam duff, while donn oc and the sons of magnus with the new levies of sil murray plundered mac gosdelb and tir maine as far as athlone."" it was in response to this that richard mor de burgh led an army into connacht ""and desolated a large portion of that country." de burgh brought with him felim mac cathal crobderg ua conchobair whom he intended to make king in place of aedh. they crossed the shannon at athlone and made straight for gallimhe.