Fionn mac Cumhail (Finn Mac Cool) was the son of Cumhail who was slain by Goll mac Morna. Cumhail left behind a pregnant Muirne who bore a handsome fair haired child and fearing the wrath of the Clan Morna she named him Demne and sent him to be fostered. He was raised a fierce warrior skilled at weaponry and fighting as well as healing and magical arts. He could never reveal his true identity but due to his fair hair he became known as Fionn. Fionn is a semimythical character said to have been an Irish warrior was the greatest leader of the Fianna an ancient military elite founded 300BC responsible for the protection of the High King. Fionn implemented a code of honour into the Fianna that had previously a reputation for being somewhat unruly thinking themselves to a small degree as above the law.
Fionn also had a son called Oisín, who was a great poet. Oisín is said to have recorded many of his father’s great fetes in poems. Oisín’s final resting place is located just outside Cushendall.
Finn’s father, Cumhail, engages Urgriu (er-gru) in battle for the position of Chieftain of the Fianna. Cumhail is wounded and his attacker carries off his pouch of magical objects. Lacking his pouch, Cumhail is slain by a member of the Morna clan, who beheads him. Slain, Cumhail leaves behind a pregnant wife, Muirne, who gives birth to a beautiful fair-haired boy. Fearing for her son’s life at the hands of Clan Morna, she sends him to the forest to be raised by Bodhmal the Druidess and her sister, the warrior Liath Luachra. Reared by these strong, wise women and tutored by the Druid Finegas as well, Demne grew to become a fierce warrior skilled at weaponry and fighting as well as at the healing and magical arts. Unable to reveal his name lest clan Morna discover him, he becomes known as “Fionn”, meaning “fair or fair-haired”.
The druid Finegas catches the Salmon of Knowledge and gives it to him to cook. Finn burns himself while doing so and sucks his thumb, thus acquiring the gift of prophecy, which he uses to ensure his survival, bring peace to his homeland, and inspire the Fianna to greatness.
Fionn gains command of the Fianna by saving the life of the High King Cormac mac Airt, who much later promises his daughter Gráinne (grahn-ya) to him in gratitude for a lifetime of service. Gráinne, however, loves another man, with whom she flees. A large part of ballads and legends of Finn MacCool concern his sixteen-year pursuit of Gráinne and her lover. Eventually he makes peace with them; they set up house near Finn and have four sons and a daughter.
He has a series of adventures involving hunting, fighting, sorcery, love, and passion. Finn has many romances but it is with the goddess Sadb that he begets his famous son, Oisín (Ossian).
In one legend, he is the creator of the Giant’s Causeway, a peculiar series of volcanic rock formations on the coast of Ireland. One day, Finn grows angry when he hears that a Scottish giant is mocking his fighting ability. He throws a rock across the Irish Sea to Scotland; the rock includes a challenge to the giant.
The Scottish giant quickly throws a message in a rock back to Finn, stating he can’t take up the challenge because he can’t swim to reach Ireland.
Finn doesn’t let the Scottish giant off so easily. He tears down great pieces of volcanic rock that lay near the coast and stands the pieces upright, making them into pillars that form a causeway that sretches from Ireland to Scotland. The giant now has to accept the challenge. He comes to Finn’s house. Finn, masquerading as a 18-foot baby, bites the Scottish giant’s hand and then chases him back to Scotland, flinging huge lumps of earth after him. One of the large holes he creates fills with water and becomes Lough Neagh, the largest lake in Ireland. One large lump of earth misses the giant and falls into the Irish Sea; this lump is now known as the Isle of Man.
There are varying accounts of Finn’s death. One tale is that he is killed while stopping a fight between members of the Fianna. Another version is that he in fact does not die at all, but is sleeping in a cave, waiting to awaken and defend Ireland in her greatest hour of need.