Oisin was one of the few mortal men to ever be invited to Tir Nan
Og. He was the son of Finn, chief of the Fenian wariors of
Ireland. One day while hunting, he was appproached by a beautiful
maiden. She was Niamh, daughter of Manannan, the god of the sea. She
chose Oisin to be her lover and to come live with her in Tir Nan
Og. They rode together over the sea on her faerie horse and visited
many strange and beautiful places. At one of them Niamh asked Oisin to
free a Tuatha de Danann damsel from a Fomor demon, which he did,
defeating the Fomor. Oisin spent 300 years with Niamh in Tir Nan Og,
before he became homesick for his people and birthplace. Niamh provided
him with a faerie steed and warned him that he must not set foot on
the earth. Arriving back in Ireland he noticed that much had changed,
the Fenians were only a myth, and the men were smaller and
weaker. While observing, he leaned down to help a man lift a boulder,
as he did so he slipped from the saddle and landed on the
sand. Instantly he was transformed into an old blind man. He wandered
Ireland for many years before St. Patrick took him into his house and
tried to convert him to Christianity. Oisin refused saying that he
could not hounour a god who would not count Finn amoung his friends,
and would rather spend eternity in Hell with the Fennians living in
death as he had life, than go to St. Patrick's heaven.