 Although the chronicle indirectly implies that Rögnvaldr was also a son of Finnguala , there is evidence that strongly suggests that he had a different mother . Within a letter from Óláfr to Henry II , King of England , Óláfr describes Rögnvaldr as a bastard . Further evidence is found within a Gaelic praise @-@ poem of Rögnvaldr , which states that he was a son of Sadb , an otherwise unknown Irishwoman who may have been an unrecorded wife or concubine of Guðrøðr . The chronicle records that because Óláfr was only a child at the time of his father 's death , the Manxmen chose Rögnvaldr to rule instead , describing him as a vigorous and hardier man . The chronicle states that Rögnvaldr began his reign the following year , in 1188 . 
