The origin of Somerled, from whom the clan derives, is obscure. Only the name of his father is directly attested in early records. He was later portrayed as having Gaelic ancestry, with late pedigrees from the 14th and 15th century tracing him from legendary Colla Uais and hence from Conn of the Hundred Battles, and some versions apparently including the legendary founder of the Scottish state of Dál Riata, Fergus Mór. Historians have distrusted this derivation, though in the 1960s, David Sellar defended a Gaelic derivation. More recently, historian Alex Woolf has pointed out the conflicting information found in the different versions of the pedigree, and drawn attention to their faulty chronology. Instead he argues that these pedigrees may derive from an original claim to the descent of Somerled from the Crovan dynasty and the Uí Ímair, subsequently obscured by alterations made to link them to the Scottish and Irish foundation legends. In any case, the Clann Somhairle based their claim to the Isles on their descent from Somerled's wife, Ragnhildr, the daughter of king Amlaíb Derg, and Woolf accepts that the male-line Crovan descent claim underlying the pedigrees may have arisen as a replacement for this female-line derivation from the family. Sir Iain Moncreiffe attempted to reconstruct a male line descent from Somerled back to Echmarcach mac Ragnaill, King of the Isles, but this has received little attention. The Orkneyinga saga refers to Somerled having "dominion in Dalr" and records that his family are known as the Dalverjar—literally "dale-dwellers". W. F. Skene suggested that although the words have quite different meanings that this name was linked to the earlier pre-Norse kingdom of Dál Riata.
Clan Gothofred
's 1549 Description of the Western Isles of Scotland offers a brief description of the five main branches of Clan Donald that existed in his day under the title "Heir Followis The Genealogies Of The Chieff Clans Of The Iles". Monro also states that in earlier days the House was known as "Clan Gothofred".
This Somerle wes the sone of Gillebryde M'Gilleadam, name Vic Sella, Vic Mearshaighe, Vic Swyffine, Vic Malgheussa, Vic Eacime, Vic Gothefred, fra quhome they were called at that time Clan Gothofred, that is, Clan Gotheray in Hybers Leid, and they were very grate men in that tymes zeire.
The name "Gofraid" also appears in numerous other versions of Somerled's ancestry. Similarly, a poetic address to Aonghus of Islay describes Clann Somairle as having "sprung from Síol nGofraidh" and a recently rediscovered poem from a 17th-century manuscript written by Niall MacMhuirich addressed to Domhnall mac Raghnaill, Rosg Mall has the line:
