Claíomh Solais (reformed spelling), Claidheamh Soluis (unreformed Mod. Ir.) is an Irish term meaning “Sword of Light”, or “Shining Sword”, which appears in a number of orally transmitted Irish folk-tales esp. of the “adventure in the otherworld (giant’s land)” variety. It also appears in numerous Scottish Gaelic folk-tales.
Recent popularized notions equate this weapon with swords from Irish mythology (Cúchulainn’s sword Cruaidín, or Nuada’s sword, one of the Four Treasures of the Tuatha Dé Danann), but this is not founded on solid literary evidence. A paragraph at bottom will be devoted to the discussion of this comingling, but the present article centers on the survey of the sword of light as they actually occur in stories passed down in the olden days.
The folk tales featuring the claidheamh soluis typically compels the hero to perform (three) sets of tasks, aided by helpers, who may be a servant woman, “helpful animal companions”, or some other supernatural being. The majority of are also bridal quests (or involve the winning of husbands in e.g., Maol a Chliobain).
The adversary is usually described as a giant (guragach or fermór), who oftentimes cannot be defeated except by some secret means. Thus the hero or helper may resort to the sword of light as the only effective weapon against this enemy. But often the sword is not enough, and the supernatural enemy has to be attacked on a single vulnerable spot on his body. The weak spot, moreover, may be an external soul concealed somewhere in the world at large (inside animals, etc.), and in the case of “The Young King of Esaidh Ruadh”, this soul is encased within a nested series of animals.
The crucial secret to the hero’s success is typically revealed by a woman, i.e., his would-be bride or the damsel in distress (the woman servant held captive by giants), etc. And even when the secret’s revealant is an animal, she may in fact be a human transformed into beast (e.g. the great grey cat in “The Widow and her Daughters”). The woman as the possessor of the secret seems to be an element of preeminent importance, suggested by the fact that one tale bears the title “The Shining Sword and the Knowledge of the Cause of the One Story about Women” (and Kennedy’s tale Fios Fath an aon Sceil or ‘perfect narrative of the unique story' may be a corruption of this). A parallel to this is the question “What is it that women most desire?” posed in the Arthurian tale of The Wedding of Sir Gawain and Dame Ragnelle, which may be a basis for further comparative analysis.
The assertion that Calidheamh soluis is “a symbol of Ireland attributed in oral tradition to Cúchulainn” (Mackillop) does not seem very representative, since in the body of folktales that mention the sword of light (listed above), few (if any) names Cuchulainn as the protagonist. And T. F. O'Rahilly only went as far as to suggests that the “sword of light” in folk tales was a vestige of Cúchulainn’s Cruaidín Catutchenn. This sword (aka “Socht’s sword”) is said to have “shone at night like a candle” according to a version of Echtrae Cormaic (“Adventures of Cormac mac Airt”).
In some circles, the Claidheamh Soluis has been asserted to be the sword of Nuada Airgedlamh, one of The Four Treasures of the Tuatha Dé Danann. This has practically become gospel among a considerably large populace in Japan, where this information was disseminated by the fantasy related mythology reference. It has been reported that artist Jim Fitzpatrick had been the one who identified Nuada’s sword as the Claidheamh Soluis in his novels (Book of Conquests (1978), The Silver Arm (1981), and Érinsaga (1985)).
There is slim literary grounds for calling Nuada Airgedlamh’s sword the Claidheamh Soluis. One scrap of text that might encourage the notion is found in the Scéla Conchobuir meic Nessa, where one of the eighteen shields (or swords) of Ulstermen is called “the Candle of Nuada” (Irish: Chaindel Nuadat, Kinsella tr. “Nuadu’s Cainnel—a bright torch”). This Nuada here is presumably an Ulster warrior but difficult to identify so that one is tempted to speculate the deity is meant.