the entire name is Finn Mac Cumhal. It’s probably the main Irish hero. His father, Cumahl was killed by Goll, from Morna clan, during Knock battle. His mother gave him in fosterage to Liath Luacra and Bodhmall the druidess. When he became older, he went himself in fosterage near Finegas, on Boyne River. He ate the knowledge salmon and became wise. He made several feats . He had a son : Ossian. When he became old, he was one of the main actor of the story of Diarmaid and Grainne. Nobody knows how Finn died. Some legends say he is sleeping in a cavern, other say he was so strong, as much as a giant, that he build the Giant Causeway, near Antrim.
Finn, son of Folcwald, was a legendary Frisian lord. He is mentioned in Historia Britonum, in Beowulf, and in the Finnsburg Fragment.