There was once in Ireland a band of brave heroes called the Fianna, and it is known that the leader of the Fianna, Finn MacCumail had a son named Oisin who was also a member of the Fianna. The Fianna were fierce in battle and sweet tongued, warrior poets in every sense of the word. Oisin was no different.
One day the men of the Fianna were out hunting by the ocean when Finn spotted something rapidly moving across the waves. The men of the Fianna thought it was an invader and began to ready themselves for battle. As the object drew closer the Fianna could only stand by in awe for what they saw was a beautiful woman riding a white horse galloping over the waves. The horse leapt ashore with the woman, and the men knew her to be one of the band of Sidhe. She introduced herself as Niamh, daughter of Manannan Mac Lir, god of the sea and she had traveled from Tir na nÓg, the land of eternal youth. The men were entranced by her beauty, her long golden hair, fine garments made of silk and jewels of gold and precious stones.
Niamh had heard about Oisin and his talent for reciting beautiful poetry, and after laying eyes on him immediately fell in love. After a few days in Conemmara it was time for Niamh to return to Tir na nÓg but the thought of leaving Oisin pulled at her heart and so asked Oisin to come with her to Tir na nÓg. Oisin could not refuse and so jumped on the back of Niamh’s beautiful white horse, said farewell to his father and fellow warriors and galloped across the western seas to the land of eternal youth.
It was not long before Oisin and Niamh were married with the consent of her parents who also loved Oisin very much. They had a family and relished every moment together in this land that knew no pain or sorrow. However after many years Oisin yearned to visit his family and friends in Ireland. Niamh reluctantly agreed to Oisin returning to Conemmara but made him promise never to dismount the horse while there. Oisin promised and kissed her goodbye as she cried for fear that she would never see her beloved husband again.
Oisin drifted across the waves on the back of the great white horse and soon viewed the cliffs of Conemmara in the distance. On reaching the shore Oisin rushed to his family but found their home no longer there. He traveled to Dun Aileann where the Fainna camped, and found the camp covered with weeds. Oisin asked some hunters in the field about Finn and the Fianna, and was told that they’d been dead for hundreds of years. After some confusion Oisin realized what had happened, one day in Tir na nÓg was the same as a year in Ireland, Oisin had been gone for hundreds of years. The only thing for Oisin to do now was travel back to Tir na nÓg and so headed for the coast of Conemarra. On the way he met some hunters struggling to move a large rock and could not bear to watch them struggle so reached down hanging from the saddle to help the hunters. With one last heave Oisin slipped from the saddle and fell to the ground. What the hunters saw drained the blood from their faces and they turned as white as the horse Oisin fell from. Oisin had rapidly aged and crumbled to the ground as dust. With fright the white horse took off and galloped to the west across the ocean back to Tir na nÓg greeting Niamh who trembled with tears knowing she’d never see her beloved Oisin again.