As mentioned in the Comparative Myth reading entitled “The Roman Mercury and the Celtic Lug,” Celtic mythology tells of the invasion of Ireland by a divine race called the Tuatha Dé Danann, who, as a group, are Celtic gods. The Tuatha will eventually be forced to leave, when men take possession of the land. Many of the Tuatha will make journeys into a realm that has been called the Celtic Otherworld.
The Celts believed in a life after death, but their notion of this life and this world is quite unique. In Book 1 of Lucan’s Civil War, an epic poem that treats the conflict between Caesar and Pompey, Caesar is summoning his troops from Gaul to march into Italy. Lucan takes a moment to describe some features of Celtic belief that were fostered by their priests, the Druids, about the afterlife. Lucan mentions these beliefs in order to explain the fierce resolve of the Gallic warrior in battle; he did not seem to fear death.
According to you [Druids], the soul does not seek the silent realms of Erebus and the pallid kingdom of Dis, deep in the earth; the same spirit governs the limbs in another world" A long life stands on either side of death. (1. 454)
This Otherworld was known by many names and variously conceived. It was the Tír na nOc (“land of youth”), the Tír inna mBeo (“land of the living”), or the Tír inna mBan (“land of women”). It was a realm of unending delights, of sexual pleasure, of plentiful food and wealth, of magic and the occult. It was at one and the same time, depending on how and for what purpose one entered it, both an idyllic realm where there was no illness or disease, and every pleasure was gratified, or the ultimate field of heroic achievement, inhabited by monstrous creatures possessed of formidable strength and supernatural power.
The Otherworld appears to have operated according to a temporal movement different from that of the ordinary world. A hero who traveled for a period of time in the Otherworld would find, on his return, that a longer or shorter period of time had elapsed in the ordinary world; many years there could be a minute here, or minutes there many years here. There is a story of a hero who spent a year in the Otherworld, only to find upon his return that many centuries had passed. As soon as he set his foot back in the ordinary world, he turned to ash.
The Celtic Otherworld was beyond normal “spatial definition.” In the sources, the Otherworld seems to be many different kinds of places or one place that presents a variegated aspect, depending on the reason for the journey. The Otherworld existed in a separate plane of existence, ordered by its own internal logic. It made contact with this physical world through various points of entry or passage. Most typical was the idea of the Síd (pl. Síde), which was mound or barrow that could contain an Otherworld. But one could also gain entry through a variety of other avenues: an island, far to the west of Ireland; beneath a lake; a mansion that would suddenly appear and disappear; a weird mist; a cave; and a mystic vision. Oftentimes, inhabitants of Otherworld will summon a hero from this world to aid them against their adversaries in Otherworld; human heroism is efficacious in disputes involving the inhabitants of Otherworld, and so it was sought after.
Scholars have often pointed out the apparent inconsistency of the portrayal of the Otherworld in the primary sources. The discrepancies may be explained rather simply: as Otherworld is an idealization of human life, it is not only a place of sensual pleasure and delight, it is also a frightening abode of demons and occult powers against which a hero can test his mettle. Any wounds received would be healed and the dead brought back to life. It was in every sense an eternal life.