The son of Lir, god of the sea, who lived in Tír Na Noc or Tír Tairngiri, both Otherwordly realms, although the Isle of Man has also been named as his home. He is also associated with the paradisal Emhain Abhlach, ‘Emhain of the Apple Trees’, a realm that is usually identified with the Isle of Arran.
He is said to have raised Lugh in the Otherworld when he acted as that god’s foster father. In Wales he became known as Manawydan fab Llyr, while later tradition has also connected him with the shadowy character of Barinthus. The Welsh connection between Manannán mac Lir and Manawydan fab Llyr has always been a tenuous one, although the medieval chronicler Cormac mac Cuilennáin attempted to reconcile the connection by declaring that Manannán mac Lir was a historical navigator and merchant who traded on both sides of the Irish Sea, leading to his being regarded as a god by both Irish and Welsh. Manannán mac Lir is a primal god of the depths of the ocean, with associations with stellar navigation. He was clearly an important deity, because Ireland had a long tradition of having been invaded from the sea. He remains the only Irish sea deity abouth whom much information is recorded. There was another, named Tethra, who fought on the side of the Fomhoiré, but little more is known about him.
Manannán mac Lir is usually depicted dressed in a green cloak fastened with a silver brooch, a satin shirt, a gold fillet and wearing golden sandals. He has the ability to adopt various forms and to calm the waters or to whip them into a frenzy. On one occasion, when Bran set out for Tír Inna Mban, he was encountered driving his chariot across the waters, which he had turned into a beautiful flowery plain. Singing a wondrous song, Manannán mac Lir was accompanied by salmon that appeared as calves and lambs, the waves as flowering shrubs and the seaweed as fruit trees. Once Manannán mac Lir had passed, the sea returned to its normal state.
In his attempt to lure Cormac mac Airt to his realm in order to reward that King, Manannán mac Lir assumed the guise of a warrior and appeared to the King on the ramparts of Tara at dawn. He told Cormac mac Airt that he came from a kingdom where decay, old age, death and falsehood were unknown, and, in exchange for the promise of three wishes, gave the King a branch that held three golden apples that would regrow when the branch was shaken. A year later, as had been agreed, Manannán mac Lir returned to claim his three wishes and made off with Cormac mac Airt’s wife and children. The King set off in hot pursuit, but was enveloped in a thick mist. This cleared to reveal a beautiful plain in the middle of which stood a wondrous palace. Entereing, the King and his company were entertained by a warrior and a beautiful maiden, whom he told of his quest. Lulled to sleep by the singing of the warrior, Cormac mac Air awoke the following morning to find himself beside his wife and children. The warrior then revealed himself as Mannanán mac Lir, and he presented the King with a beautiful golden cup. Intending to set off for Tara the following day, Cormac mac Airt, his wife and children awoke to find themselves on the grass outside their home, the cup and bough of golden apples beside them.