The Dagda (Proto-Celtic: *Dagodeiwos, Old Irish: Dag Dia, Modern Irish: Daghdha) is an important god of Irish mythology. The Dagda is a father-figure (he is also known as Eochaid(h) Ollathair, or “All-father”) and a protector of the tribe. In some texts his father is Elatha, in others his mother is Ethniu. Other texts say that his mother is Danu. The Dagda’s siblings include the gods Ogma and Lir.
The Dagda was a High King of the Tuatha Dé Danann after his predecessor Nuada was injured in battle. The Tuatha Dé Danann are the race of supernatural beings who conquered the Fomorians, who inhabited Ireland previously, prior to the coming of the Milesians. His lover was Boann and his daughter was Breg. Prior to the battle with the Fomorians, he coupled with the goddess of war, the Mórrígan, on Samhain in exchange for a plan of battle.
Despite his great power and prestige, the Dagda is sometimes depicted as oafish and crude, even comical, wearing a short, rough tunic that barely covers his rump, dragging his great penis on the ground.
The Dagda had an affair with Bóand, wife of Elcmar. In order to hide their affair, Dagda made the sun stand still for nine months; therefore their son, Óengus, was conceived, gestated and born in one day. He, along with Bóand, helped Óengus search for his love.
Whilst Aengus was away the Dagda shared out his land among his children, but Aengus returned to discover that nothing had been saved for him. Under the guidance of Lugh Aengus later tricked his father out of his home at the Brú na Bóinne (Newgrange). Aengus was instructed to ask his father if he could live in the Brú for láa ogus oidhche “(a) day and (a) night”, which in Irish is ambiguous, and could refer to either “a day and a night”, or “day and night”, which means for all time, and so Aengus took possession of the Brú permanently. In “The Wooing of Étaín”, on the other hand, Aengus uses the same ploy to trick Elcmar out of Brú na Bóinne, with the Dagda’s connivance.
The Dagda was also the father of Bodb Dearg, Cermait, Midir, Aine, and Brigit. He was the brother or father of Oghma, who is probably related to the Gaulish god Ogmios; Ogmios, depicted as an old man with a club, is one of the closest Gaulish parallels to the Dagda. Another Gaulish god who may be related to the Dagda is Sucellus, the striker, depicted with a hammer and cup.
He is credited with a seventy or eighty-year reign (depending on source) over the Tuatha Dé Danann, before dying at the Brú na Bóinne, finally succumbing to a wound inflicted by Cethlenn during the second battle of Magh Tuiredh.