This post concerns the cohuleen druith (a kind of magic sea hat), and all its variants in Irish and Scots folklore.
Firstly, on the name. Sometimes I’ve seen the first word spelled ‘cohuleen’ and sometimes ‘cohullen’, but in either case its meaning is clear, being derived from Irish cochall, or ‘hood’. ‘Druith’ is desrived from draoi. I will qoute MacBain’s definition here:
draoi, druidh, a magician, druid, Irish draoi, gen. pl. druadh, Early Irish drai, drui, g. druad, Gaulish druides (English druid). Its etymology is obscure. Stokes suggests relationship with English true, Gaelic dearbh, q.v. Thurneysen analyses the word as dru, high, strong, See truaill. Brugmann and Windisch have also suggested the root dru, oak, as Pliny did too, because of the Druids’ reverence for the oak tree. Anglo-Saxon dry/, magus, is borrowed from the Celtic. draoineach, druineach, artisan, “eident” person (Carm.); draoneach, “any person that practices an art” (Grant), agriculturist; druinneach, artist (Lh.). Irish druine, art needlework.
Therefore the “druid’s hood”, or enchanted hood, is used by the Irish Merrow (sea people) to make journeys from the undersea realms to the surface and back again (Yeats, as ever, provides a good basic source for this). If a merrow loses its hat, or if it is stolen by a human, that merrow cannot return to the undersea realm. In many accounts, this particular fact is a useful means by which men may kidnap female merrow and force them to live in marriage on the surface, as in the story of the Lady of Gollerus. And I think that is its main function. My supposition here is that the cohuleen druith was invented by Irish story-tellers to make the “kidnapped mermaid” motif seem more plausible and more interesting, and also to allow human visitors to see and report on the remarkable undersea realm.
My reason for this is pretty simple: there doesn’t seem to have been a conceptual problem in Gaelic folklore with the idea of undersea humanoid creatures that could breathe water – in fact, the Blue Men of the Minch are a case in point (although in my version of the Blue Men story, they do use magic hats), as are various trows, nuggles and other sea sprites that do not seem to need a cohuleen druith to survive underwater. So, if the only reason for the cohuleen druith was to explain how creatures could breathe, it would have no function at all in the narrative, as pre-modern audiences would happily listen to a tale about a free-swimming aquatic humanoid creature with no apparent air supply.
However, there did need to be some explanation as to why a kidnapped mermaid did not simply run away. Here, the cohuleen druith is perfect, a ready made reason why she must stay until, like the Lady of Gollerus, she discovers it’s hiding place and departs at once to her true element, leaving a lingering doubt as to the fishy maternal origins of everyone in the family thereafter.
But in other situations, it will serve as an explanation for why a human is capable of visiting the undersea kingdom, like in Crofton Coker’s The Soul Cages, in which the hat is described as being like a cocked hat. Here, the human protagonist is capable of visiting the undersea world of the mysterious merrow through the aid of a borrowed hat.
Scottish material has interesting parallels to the Irish; George Douglas (1901) provides us with The Fisherman and the Merman, The Mermaid Wife and The Seal-Catcher’s Adventure, all of which abandon the cohulen druith in favor of seal skins, and two of which are from the Shetlands. In all of these tales the merrow appear as being very similar to the Selkie, taking the form of seals while travelling and then disrobing of their seal skin apparel when on the shore. In each one, a skin gets stolen, with tragic consequences for the owner, who can no longer return below.
The Scots / Norse influenced use of the sealskin for exactly the same narrative purpose as the cohulen druith has further convinced me that it is a narrative device with little background in earlier Celtic lore. I’d be interested in read any accounts of enchanted hats being worn by merrow in the Irish cycles, which is would we would expect to find them if they were a part of ancient tradition. But to my knowledge, there are none; as far as I can see, the ‘enchanted hat’ is like an 18th century equivalent of the teleporter on Star Trek: it’s a very handy scenic device when it’s working, and a very handy plot device when for some reason – like in nearly every episode – it doesn’t.
As I mentioned, in my Blue Men of the Minch story, the titular creatures wear magic hoods, although they do not in MacKenzie’s original. I merged the merrow and the Blue Men in this way precisely because I wanted to have the ‘stolen wife’ element in the story, and for my protagonist to see the under sea kingdom beneath the Shiant Isles. And without the cohulen druith, that’s simply not possible. In fact the story didn’t really come alive until I added the hat. Handy, that.
Find out more about the Blue Men, Green Women series here...