Niamh is a character from Irish mythology, known for her beauty and bravery. She is often associated with the Tuatha Dé Danann, a mythical race of deities in Irish folklore. Niamh is the daughter of the sea god Manannán mac Lir and is famous for her adventures with Oisín, a legendary warrior and poet. In the tales, Niamh travels to the magical land of Tír na nÓg, which means "Land of Eternal Youth." She invites Oisín to join her, promising him a life free from aging and sorrow. Their story highlights themes of love, adventure, and the passage of time in Celtic mythology.