The break up of the kingdom of the Isles
By David Caldwell
West Highland Notes and Queries, Series 3, no. 14. (2009)
Introduction: For the history of the Isles in the 12th and 13th centuries historians are very dependent on the Chronicles of the Kings of Man and the Isles, written from a Manx perspective, perhaps mostly in 1257. With few or no other sources to provide corroboration for many events, there has, perhaps, been a tendency to accept the Chronicles’ version of events uncritically. An example of this is the division of the Kingdom of the Isles in 1156 between the Manx king, Godred Olafsson, and a local strongman, Somerled. This is understood to have created a situation where Godred and other kings based in Man controlled that island as well as Lewis and Skye, while Somerled and his descendants (the MacSorleys) took the Uists and Barra, the Mull and Islay groups of islands, and also Arran. There is a tacit understanding that the Manx kings continued to hold Lewis and Skye until Man and the Isles became part of the kingdom of Scotland as a result of the Treaty of Perth in 1266.
What the Chronicles actually say (in the translation by George Broderick) is:
In the year 1156 a naval battle was fought on the night of the Epiphany between Godred and Somerled and there was much slaughter on both sides. When day dawned they made peace and divided the kingdom of the Isles between them. The kingdom has existed in two parts from that day up until the present time, and this was the cause of the break-up of the kingdom from the time the sons of Somerled got possession of it.