 Some time in the 1010s , Brian Boru divorced his second wife , the thrice married Hiberno @-@ Norse Queen Gormflaith , and she began engineering opposition to the High King . Around 1012 , relations between Brian and Leinster had become so strained that revolt broke out among the Leinstermen . Gormflaith sent her son , the King of Dublin , Sigtrygg Silkbeard , to win first the support of Earl Sigurd of Orkney , and then of Bróðir and Óspak , at any price . Sigtrygg went to Man , where he persuaded Bróðir to come to Dublin by Palm Sunday . Sigtrygg promised both Sigurd and Bróðir separately that , if successful , they would be allowed marry Gormflaith and become High King of Ireland ; the terms of this agreement , however , were to be kept secret . Óspak was dissatisfied with the arrangement , and refused to " fight against so good a king " . 
