 The campaign is regarded to have been the gravest threat to the Scottish kingdom since John , King of England 's ( d . 1216 ) northern campaigning and invasion in 1216 . Although Óláfr 's restoration on Mann was claimed as a success by the Norwegians , it was probably accepted gladly by the Scots as well ; considering Óláfr 's familial relationship with Alexander 's protégé Ferchar and the consolidation of the Crovan dynasty after years of chaos . Óláfr consequently ruled the Kingdom of Mann and the Isles peacefully until his death , seven years later . The chronicle states that he died on St Patrick 's Isle on 21 May 1237 and was buried at St Mary 's Abbey , Rushen . There is a possibility that a coffin @-@ lid or grave @-@ slab found at Rushen may be associated with Óláfr , or of two of his sons who are known to have been buried there ( Rögnvaldr and Magnús ) . 
