Þórkell Þórmóðarson, were ancestors of Clan MacLeod. The Old Norse names Þórmóðr and Þórkell are the ultimate origin of the modern Scottish Gaelic names Tormod and Torcall. Thomas noted that the traditionally the clan is said to have two branches—one is traditionally known in Scottish Gaelic as Sìol Thormoid ("Seed of Tormod"), the other is known as Sìol Thorcaill ("Seed of Torcall"). Historically, Sìol Thorcaill was the dominant family on Lewis from the Late Middle Ages to the end of the 16th century. Sìol Thormoid has held lands in western Skye since the Late Middle Ages, and descendants (in the female line) of the original chiefly line are still seated on the shores of Loch Dunvegan. According to clan tradition, the two branches take their names from two brothers who were sons of the clan's founder—Torcall and Tormod, sons of Leod. However, the current understanding of the origin of these branches is that these two men were not brothers, but one was a grandson of the other—Torcall was the grandson of Tormod, who was the son of Leod. Leod and his son, Tormod, do not appear in contemporaneous historical records; although Torcall does, in the mid 14th century. Thomas believed that the eponymous ancestor of the clan was Ljótólfr, a character in the mediaeval Orkneyinga saga, which depicts him as a 12th-century nobleman from Lewis. The currently accepted understanding of the clan's origin is that the clan's eponym was another man, named Leod (a name derived from the Old Norse Ljótr), who is thought to have flourished about a century after the time of Ljótólfr. While the current understanding of Leod's ancestry does not include a man named Ljótólfr, the 20th-century clan historian Alick Morrison considered it possible that Ljótólfr could be an ancestor, albeit on his distaff side. Thomas proposed that Þórmóðr Þórkelsson was the surviving son of Þórkell Þórmóðarson; and that Þórkell Þórmóðarson was in turn the grandson of Ljótólfr. Thomas pointed out that, since the saga states that Þórkell left behind his wife and possessions on Lewis when he fled the returning fleet, the saga shows that Þórkell was a resident on that island. Thomas theorised that a generation could be estimated to about 30 years, and noted that Þórkell was married in about 1231. Thomas estimated that Þórmóðr was born in 1201; his (supposed) father, Þórkell, in 1171; Þórkell's father Þórmóðr in 1141; and this man's