Eirspennill, the Flateyjarbók, the Frisbók, and the Skálholtsbók. According to twentieth-century historian Alan Orr Anderson, although the Eirspennill version may be of a later date than the others, it is the most authoritative, and likely represents an early form of the saga. Historical background In the early 12th century, the Kingdom of Mann and the Isles encompassed the Hebrides and the Isle of Man. In 1156, Guðrøðr Óláfsson, King of Mann and the Isles, fought an inconclusive naval battle with Somairle, Lord of Argyll, and the kingdom lost control of parts of the Inner Hebrides, although retained control of Skye. In 1187, Guðrøðr died, and had intended to that his young son Óláfr would succeed him. The Manx people, however, chose Guðrøðr's elder, although illegitimate son, Rögnvaldr. Bitter feuding between the two half-brothers in the late 12th and early 13th century severely weakened the kingdom. At one point, Rögnvaldr's son Guðrøðr drove Óláfr out of kingdom, only to be defeated by Óláfr, and then blinded and castrated by one of Óláfr's accomplices. In the early 13th century, Alan, Lord of Galloway had sights set on the Isle of Man; his illegitimate son was married to the daughter of Rögnvaldr, King of Mann and the Isles. Both Alan and his brother, Thomas, Earl of Atholl, backed Rögnvaldr against Rögnvaldr's half-brother, Óláfr. In 1226, Óláfr ejected his brother from the Isle of Man, and ruled the kingdom for the next 11 years (Rögnvaldr was slain in 1229, fighting against Óláfr). Because of Óláfr's inability to control the warring in the Hebrides, Hákon Hákonarson, King of Norway, promoted Óspakr, a descendant of Somairle, as king in the Isles. Hákon gave Óspakr command of a fleet to establish himself in all of the Scottish islands, and according to historian G.W.S. Barrow, possibly Argyll and Kintyre as well. Both Óláfr, and his nephew, Guðrøðr, accompanied the fleet as it sailed down through the Hebrides in the spring of 1230. If the saga accounts are to be believed, the fleet totalled eighty ships, and according to historian Richard Oram, this likely equates to a force of over three thousand men. When the fleet reached the southern Hebrides, several grandsons of Somairle, who had sided with Alan, were captured and taken prisoner. The fleet likely entered the Firth of Clyde in early June, and the force attacked the Isle of Bute. Although the Norwegian-Hebridean force was successful