Oisín

Oisín ("little deer" or "young deer") is the son of Fionn mac Cumhaill and Sadhbh, a woman transformed into a deer by a dark druid's curse — a shape she is trapped in when Fionn's hounds Bran and Sceólang find and befriend her, allowing her to briefly resume human form and conceive Oisín before the druid recaptures and curses her again, permanently, while Fionn is away. Fionn raises the boy alone, finding him as an infant in the very spot where he first found Sadhbh as a deer, which gives Oisín his name. Oisín grows to become the Fianna's finest poet, and his own most famous tale takes him out of the cycle's usual world entirely. Niamh of the Golden Hair, a woman from the Otherworld realm of Tír na nÓg ("the Land of Youth"), comes to invite him to live with her there, and he departs Ireland on her white horse. In Tír na nÓg, time does not pass as it does in the ordinary world, and though Oisín believes he stays only a few years, centuries pass in Ireland. When homesickness eventually draws him to visit, Niamh warns him never to dismount or touch the ground — but when he leans down to help some men move a boulder, his saddle-girth breaks, he touches Irish soil, and instantly becomes an old, withered man, all the years he never aged catching up with him at once. This frame — an aged Oisín, the last of his generation — sets up the *Acallam na Senórach* (The Colloquy of the Ancients), in which he and fellow survivor Caílte meet Saint Patrick and recount the deeds of the Fianna to him, providing the narrative device through which much of the Fenian Cycle's material is said to have been preserved and transmitted into the written tradition.