altar Smertullos is attacking an eel or serpent.  Hence Pollux is Smertullos-Cuchulainn.[486] Again, the name Cernunnos signifies “the horned one,” from cernu, “horn,” a word found in Conall’s epithet Cernach.  But this was not given him because he was horned, but because of the angular shape of his head, the angle (cern) being the result of a blow.[487] The epithet may mean “victorious."[488] On the whole, the theory is more ingenious than convincing, and we have no proof that the figures of Castor and Pollux on the altar were duplicates of the Celtic pair.  Cernunnos was an underworld god, and Conall has no trace of such a character.

M. D’Arbois also traces the saga in Gaul in the fact that on the menhir of Kervadel Mercury is figured with a child, Mercury, in his opinion, being Lug, and the child Cuchulainn.[489] On another altar are depicted (1) a woodman, Esus, cutting down a tree, and (2) a bull on which are perched three birds—­Tarvos Trigaranos.  The two subjects, as M. Reinach points out, are combined on another altar at Treves, on which a woodman is cutting down a tree in which are perched three birds, while a bull’s head appears in the branches.[490] These represent, according to M. D’Arbois, incidents of the Tain—­the cutting down of trees by Cuchulainn and placing them in the way of his enemies, and the warning of the bull by Morrigan in the bird form which she shared with her sisters Badb and Macha.[491] Why, then, is Cuchulainn called Esus?  “Esus” comes from a root which gives words meaning “rapid motion,” “anger,” “strength”—­all shown by the hero.[492] The altars were found in the land of the Belgic Treveri, and some Belgic tribes may have passed into Britain and Ireland carrying the Esus-Cuchulainn legend there in the second century B.C., e.g. the Setantii, dwelling by the Mersey, and bearing a name similar to that of the hero in his childhood—­Setanta (Setantios) as well as the Menapii and Brigantes, located in Ireland by Ptolemy.[493] In other words, the divine Esus, with his surname Smertullos, was called in Ireland Setanta, after the Setantii, and at a later date, Cuchulainn.  The princely name Donnotaurus resembles Dond tarb, the “Brown Bull” of the saga, and also suggests its presence in Gaul, while the name [Greek:  deiotaros], perhaps the equivalent of De[^u]io-taruos, “Divine Bull,” is found in Galatia.[494] Thus the main elements of the saga may have been known to the continental Celts before it was localised in Ireland,[495] and, it may be added, if it was brought there by Gallo-British tribes, this might account for the greater popularity of the native, possibly pre-Celtic, Fionn saga among the folk, as well as for the finer literary quality of the Cuchulainn saga.  But the identification of Esus with Cuchulainn rests on slight grounds; the names Esus and Smertullos are not found in Ireland, and the Gaulish Esus, worshipped with human sacrifice, has little affinity with the hero, unless his deeds of slaughter are reminiscent of such rites.  It is possible, however, that the episode of the Tain came from a myth explaining ritual acts.  This myth may have been the subject of the bas-reliefs, carried to Ireland, and there worked into the saga.