Charles Squire writes, "The most common antagonists of Finn and his
heroes are tribes of invaders from oversea, called in the stories the
Lochlannach. These "Men of Lochlann" are usually identified, by those
who look for history in the stories of the Fenian cycle, with the invading
bands of Norsemen who harried the Irish coasts in the ninth century. But the
nucleus of the Fenian tales antedates these Scandinavian raids, and mortal
foes have probably merely stepped into the place of those immortal enemies
of the gods whose "Lochlann" was a country, not over the sea -- but under it."
It's hard to believe that these "Men of Lochlann," from whom the
tales of selkies are born, would ever be associated with the violent nature
of the Vikings, or with any aggressive invading tribe. But as stated earlier,
the Irish cultivated a healthy respect -- and often fear -- of anything that
came from under the ocean, because those who lived beneath its waves were
familiar with the mysterious lands beyond what mortals could fathom or
understand.