Nennius was a Welsh monk of the 9th century who is traditionally attributed with the authorship of the ‘Historia Brittonum’, the History of the Britons. This is a purported history of the indigenous British (Brittonic) people that was written around 828 CE and survives in numerous recensions that date from after the 11th century.
When AW Moore published his ‘Manx Folklore’ in 1891 he quoted a record by Nennius of ‘the Three Wonders of the Isle of Man’. Translated from its original Latin, the Nennius quotation reads:
“The Wonders of Manann down here. The first wonder is a strand without a sea. The second is a ford which is far from the sea and which fills when the tide flows and decreases when the tide ebbs. The third is a stone which moves at night in Glen Cindenn, and though it should be cast into the sea, or into a cataract, it would be found on the margin of the same valley.”
The first wonder, “a strand without a sea,” is, like so many old Manx traditions, connected with Mananan-beg-mac-y-Leirr – “Him that could make a thing like a sea where no sea was, and a shore where no wave was” – and the strand without a sea is said to have been Sulby Claddagh. Cronk Sumark (primrose hill), rising just behind the Claddagh, is one of the places where Mananan used to dwell on occasion, and many old stories formerly well known in the neighbourhood relate how he has been seen on its summit in the midst of his White Host of fairy warriors, all of them half-veiled in sweeping mist; and how when enemies or undesirable folk approached he would make the Cronk appear to be an island surrounding it by a billowing sea, so that they retired in panic, thinking the land was being overwhelmed. But as the horses of the White Host charged down the hill to pursue them, their hooves were treading only sharp grey sand when they reached the Claddagh and they had only a shallow river to ford.
There is still a sharp grey sand to be found on Sulby Claddagh – but who today, glimpses in the mists that swirl around Cronk Sumark, Mananan and his Host? Yet it is not very many years since I was told by a Sulby woman that if the Island is ever in dire peril, Mananan and his Host will come to deliver us. It is the old theme, traditional throughout the Celtic lands, of the hero-king held under spells or departed to the Otherworld – Arthur of Britain in his cave, Finn and the Fianna in the land of shades – awaiting the summons of the nation they served in life to return and save it when all else fails. Mananan is the hero-image of our Manx heroic past, and perhaps a personification of the essential spirit of our race.
(source: photo of Cronk Sumark by Chris Gunns http://bit.ly/1b51mlx; This is Ellan Vannin Again: Folklore by Mona Douglas (1966))