One of the deities that can be found in the mythology of several different Celtic nations is Manannán; called Manannán mac Lir (son of the sea) in Ireland, and Manawydan to the Welsh. His home was said to be the Isle of Man, called Manaw in Welsh and Manu in Irish; Manannán's name clearly derives from this and since this name for the island is a later development O hOgain posits that Manannán himself and his mythology are later developments as well, likely dating to no earlier that the 3rd century CE (O hOgain, 2006). The Irish initially borrowed the name from the Welsh, but then added the title "mac Lir" which was then borrowed into the Welsh as "map Llyr" (O hOgain, 2006). This demonstrates the composite nature of Manannán that has developed over time as the cultures shared mythology back and forth. To the Manx he was the first king of the Island of Man, and stories locate his grave there, as well as tell of how he would walk among the Manx fishermen as they repaired their nets (Monaghan, 2004).
Manannán appearance is described as being that of a handsome warrior (Berresford Ellis, 1987). Manannán's wife is Fand, a peerless beauty who at one point had an affair with Cu Chulain, until Manannán used his magic to make Cu Chulain forget about her and return to his own wife, Emer. It is said that Manannán traveled to the mortal world to father Mongán, a prince and hero, and under the name of Oirbsiu he may have fathered the Conmhaicne sept of Leinster (O hOgain, 2006). There are many stories about his various sons and daughters, who are usually treated as minor characters (O hOgain, 2006). One of his more well known children is Aine, although some sources list her as his wife.
Manannán was originally said to live on the Isle of Man, a place which was seen as near mythical in Irish stories; later his home shifted fully into the Otherworld, to Eamhain (O hOgain, 2006). The Irish described Eamhain in rich detail as a sacred place, an island held up by four silver legs or pillars, on which grew magical apples which gave the island the full name of Eamhain Abhlach, Eamhain of the Apples (O hOgain, 2006). Other names for his domain include Mag Meall (the pleasant plain) and Tír Tairngire (the land of promise) (O hOgain, 2006). Each of these names and associations reflect the connection between Manannán's realm and the Otherworld.
To the Welsh Manannán - or more properly Manawydan - was a skilled craftsman and trickster deity (O hOgain, 2006). To the Irish, however, he was seen as the lord of the waves, to whom the ocean was like a field of solid land, as well as a master magician and God who could control the weather (O hOgain, 2006). The fish are said to be his livestock, compared to cows and sheep, and the waves themselves are called his horses; his most special horse is Enbharr, 'water foam', who could run over sea as if it were solid land (O hOgain, 2006). In the story of his meeting with king Cormac mac Art he is described as carrying a golden apple branch that rang with sweet music that could sooth people to sleep or heal the ill and wounded (O hOgain, 2006). Some sources consider him a shapeshifter, and his magical powers were numerous; he could travel faster than the wind could blow in his magical boat, he could create realistic illusions, and he had a cloak of forgetfulness that would take the memory from a person (Monaghan, 2004). It was this cloak that he used to cause Cu Chulain to forget Fand in the story of the Only Jealousy of Emer.
In Irish mythology, although he was not counted among the People of Danu in stories until the 10th century, it is Manannán who advises the Tuatha de Danann to take up residence in the sidhe, and he who assigned each new home (O hOgain, 2006). Additionally, he gives three gifts to the Tuatha de; the féth fiadha, the feast of Goibhniu, and the pigs of Manannán (O hOgain, 2006). The féth fiadha was either a spell or cloak that allowed the person to become invisible and travel unnoticed. The feast of Goibhniu was a magical feast that kept the gods young and living. And the pigs of Manannán were immortal swine who could be killed and would return to life. Some sources suggest that it was these actions that earned him a place among the Tuatha de Danann, however I believe that it is more likely that he fills a role as an outsider deity, not fully part of the People of Danu nor fully seperate but liminally placed. Even his realm which is a land that is not part of the land reflects this idea.
Manannán's nature is as mercurial as the sea. When visiting Elcmar at his sidhe he is paid great tribute with rushes laid out before him and a great feast prepared, yet despite the pleasant visit he dislikes Elcmar and acts against him later (O hOgain, 2006). In the stories of the Fianna Manannán is often helpful yet also appears at least once to stir strife and create trouble among the warriors (O hOgain, 2006). This could reflect the knowledge of all sailors that the favor of the sea is fickle and quick to change, or perhaps Manannán's own liminal nature tends toward changeability.
In several sources rushes are mentioned as offerings for him, so it could be safely assumed that rushes were historically sacred to him (O hOgain, 2006). The sea and waters were also strongly associated with him, and it said in the story of Oirbsiu that when he died a lake burst forth from his grave. He is also strongly associated with horses and apples. Many modern neo-Druids see Manannán as the keeper of the gates between our world and the Otherworld and call on him to open the way between the worlds. Living near the ocean I tend to feel his presence in the fog and mist, as well as sometimes in the ocean waves. I believe it is important when connecting to Manannán to remember the truly awesome power of the ocean and of water, both to nourish and to destroy; power that reflects and is reflected by Manannán's own personality and actions in mythology. The same ocean that feeds and comforts us can as easily kill us if we do not respect it; the river that gives us water to drink and a place to swim can rise up in a flood and destroy our homes. Manannán can bless us or harm us, and we would be wise to remember the true nature of his power as we honor him.
Berresford Ellis, P., (1987). a Dictionary of Irish Mythology
Monaghan, P., (2004). the Encyclopedia of Celtic Myth and Folklore
O hOgain (2006). the Lore of Ireland