And concerning the previously mentioned Sweyne Assleifsson - he was a great pirate (think 'Pirates of the Caribbean'); the sort of person from whom clans could originate. But Gunns are not Sweynessonn / Swanson they are Gunns. If you believe the Gunn mythic history we are named after Sweyne's anonymous grandson. This anonymous grandson (Gunni Andresson) did nothing bar marry well. Nobody, but nobody, gets family named / surnamed after an anonymous person especially when the grandfather was so well known. And, as often said, this supposed 'Gunn Chief' line died out in Norway with Snaekoll Gunnarson see http://clangunn.weebly.com/why-gunns-are-not-of-norse--orkn…
Another reason why Sweyne Assleifsson, Gunni Andresson or Snaekoll Gunnarson descent option does not work for the Gunns is that -
'Many Scottish surnames originated in patronymics, whereby a son’s surname derived from the father’s forename, e.g. John Donaldson’s son might be Peter Johnson, whose son might be Magnus Peterson, and so on. Patronymics present something of a challenge for the family historian in that the surname changed with each successive generation. This practice died out in Lowland Scotland after the 15th century, as patronymic surnames became permanent family names. It persisted, however, in the Highlands & Islands well into the 18th century..'http://www.scotlandspeople.gov.uk/Content/Help/index.aspx…
So according to mythic Gunn Norse / Viking / Asleiffsson history the Gunn patronymic surname was fixed roughly 600 years before everyone else's surnames / family names were fixed in the Highlands of Scotland and also when all Scottish Highland society was doing something totally different to the Gunns for family names / surnames. That's impossible to accept...