 The islands were fully Christianised by Olav Tryggvasson in 995 when he stopped at South Walls on his way from Ireland to Norway . The King summoned the jarl Sigurd the Stout and said , " I order you and all your subjects to be baptised . If you refuse , I 'll have you killed on the spot and I swear I will ravage every island with fire and steel . " Unsurprisingly , Sigurd agreed and the islands became Christian at a stroke , receiving their own bishop in the early 11th century . 
