“Niamh of the lovely hair” was the daughter of the Irish Sea God, Manannan Mac Lir. She was the Queen of the Tir na n-Og, the mythological race of Faeries who lived in the Land of the Eternal Youth. She would ride on her Faerie steed “Embarr” across the waves to the West Coast of Ireland quite often.
On one of these trips, she met members of the warrior group known as the Fianna. One of the warriors, a bard named Oisin, she came to have a liking for. He fell for her with love at first sight. She quickly took him on her horse with her back to Tir na n-Og.
She was most notorious for having been the Faerie princess who lured off the great Bard Oisin to Faerieland, where they were married, and she had hoped he would have been fine residing in the Land of the Eternal Youth. There, Niamh and Oisin gave birth to a son and a daughter. Oisin’s son is “Oscar” and his daughter was “Plor na mBan”, the “Flower of Women”.
After three years in Faerie, He grew weary and tired, missing his family, and asked to return to his land to see them. She set him off on the same white magical steed that she brought him to the land of Faerie on, the horse “Embarr” (meaning “Imagination”), and warned him not to step foot off his horse when he returns to the human world. He discovered that three years in Faerie was three hundred years in Human.
He accidentally fell off Embarr when he was trying to help some farmers move a big stone, and Embarr ran home, across the waves. Poor Oisin immediately became a blind old man to wander Ireland searching for his family and his Niamh. He could never find the entrance to Tir na n-Og again. Niamh waited and waited for him, but Oisin never returned. She had become pregnant with his daughter, Plur na mBan, a beautiful Faerie princess known as “The Flower of the Lady”.
After many years, Niamh went back to the mortal world to search Ireland high and low for her sweet Oisin. She was too late, Oisin had died and disappeared forever. His tomb is somewhere up in Northern Ireland near the Giant’s Causeway. During her wanderings searching for Oisin, she met the Faeries of Brittany, who invited her to join them. She didn’t, but rather sent them a magical moving picture of herself. This upset Brittany Faeries, who placed her in a deep wood where she wandered for a long time with a light on her forehead, eternally lost. After she discovered her escape, she experienced great disappointment and anger with Brittany Fae and returned to Tir na n-Og, presumably casting a magic spell that took all of Brittany’s faerie children with her in revenge.