Celtic Otherworld

In Celtic mythology, the Otherworld is the realm of the deities and possibly also the dead. In Gaelic and Brittonic myth it is usually a supernatural realm of everlasting youth, beauty, health, abundance and joy. It is described either as a parallel world that exists alongside our own, or as a heavenly land beyond the sea or under the earth. The Otherworld is usually elusive, but various mythical heroes visit it either through chance or after being invited by one of its residents. They often reach it by entering ancient burial mounds or caves, or by going under water or across the western sea. Sometimes, they suddenly find themselves in the Otherworld with the appearance of a magic mist, supernatural beings or unusual animals. An otherworldly woman may invite the hero into the Otherworld by offering an apple or a silver apple branch, or a ball of thread to follow as it unwinds.

The Otherworld is usually called Annwn in Welsh mythology and Avalon in Arthurian legend. In Irish mythology it is Tír na nÓg. There is also Mag Mell and Emain Ablach, Tech Duinn, the last of which is where the souls of the dead gather.

In Irish mythology, the Otherworld has various names. Names of the Otherworld, or places within it, include Tír nAill ("the other land"), Tír Tairngire ("land of promise/promised land"), Tír na nÓg ("land of the young/land of youth"), Tír fo Thuinn ("land under the wave"), Tír na mBeo ("land of the living"), Mag Mell ("plain of delight"), Mag Findargat ("the white-silver plain"), Mag Argatnél ("the silver-cloud plain"), Mag Ildathach ("the multicoloured plain"), Mag Cíuin ("the gentle plain"), and Emain Ablach (possibly "isle of apples").

It is described as a supernatural realm where there is everlasting youth, beauty, health, abundance and joy, and where time moves differently. It is the dwelling place of the gods (the Tuatha Dé Danann) as well as certain heroes and ancestors. It was probably similar to the Elysium of Greek mythology^{[according to whom?]} and both may have a shared origin in ancient Proto-Indo-European religion. The Otherworld is elusive, but various mythical heroes—such as Cúchulainn, Fionn and Bran—visit it either through chance or after being invited by one of its residents. In Irish myth and later folklore, the festivals of Samhain and Beltane (Bealtaine) are liminal times, when contact with the Otherworld was more likely.

In the tales, the Otherworld is often reached by entering ancient burial mounds, such as those at Brú na Bóinne and Cnoc Meadha. These were known as sídhe ("Otherworld dwellings") and were the dwellings of the gods, later called the aos sí or daoine sí ("Otherworld folk"). Irish mythology says the gods retreated into the sídhe when the Gaels (Milesians) took Ireland from them. In some tales, the Otherworld is reached by going under the waters of pools, lakes, or the sea, or else by crossing the western sea. In Irish Immrama ("voyage") tales, a beautiful young Otherworld woman often approaches the hero and sings to him of this happy land. Sometimes she offers him an apple, or the promise of her love in exchange for his help in battle. He follows her, and they journey over the sea together and are seen no more. Their journey may be in a boat of glass, in a chariot, or on horseback (usually on a white horse, as in the case of the goddess Niamh of the Golden Hair).

Sometimes the hero returns after what he believes is a short time, only to find that all his companions are dead and he has actually been away for hundreds of years. Sometimes the hero sets out on a quest, and a magic mist descends upon him. He may find himself before an unusual palace and enter to find a warrior or a beautiful woman who makes him welcome. The woman may be the goddess Fand, the warrior may be Manannán mac Lir or Lugh, and after strange adventures the hero may return successfully. However, even when the mortal manages to return to his own time and place, he is forever changed by his contact with the Otherworld.

The Otherworld was also seen as a source of authority. In the tale Baile in Scáil ("the phantom's ecstatic vision"), Conn of the Hundred Battles visits an Otherworld hall, where the god Lugh legitimizes his kingship and that of his successors.

In Irish myth there is another otherworldly realm called Tech Duinn ("House of Donn" or "House of the Dark One"). It was believed that the souls of the dead travelled to Tech Duinn; perhaps to remain there forever, or perhaps before reaching their final destination in the Otherworld, or before being reincarnated. Donn is portrayed as a god of the dead and ancestor of the Gaels. Tech Duinn is commonly identified with Bull Rock, an islet off the west coast of Ireland which resembles a portal tomb. In Ireland there was a belief that the souls of the dead departed westwards over the sea with the setting sun, westward also being the direction in which the phantom island anglicised as Hy-Brasil was purported to be found.