 The chronicle records that in 1228 , while Óláfr and his chiefs were away from Mann , the island was attacked and devastated by Alan , his brother Thomas , Earl of Atholl ( d . 1231 ) , and Rögnvaldr . It was only when Alan left with most of his force that Óláfr was able to regain control of the island . Rögnvaldr sailed from Galloway in the winter of the same year , landed on Mann , and burnt all the ships of Óláfr and his chiefs . The chronicle states that Rögnvaldr stayed at Ronaldsway for forty days ; and that he won over the hearts of the southern inhabitants of the island . Óláfr and his forces arrived at Tynwald on 14 February 1229 , where they attacked Rögnvaldr and his men . The chronicle claims that Rögnvaldr was treacherously killed by his own men , without the prior knowledge of Óláfr , and also notes that Óláfr never avenged his half @-@ brother 's death . 
