The Children of Lir (Oidheadh Chlainne Lir)
A tragic story of four children turned into swans by their jealous stepmother, Aoife.
Lir, a lord of the Tuatha Dé Danann, had four beautiful children: Fionnuala, Aodh, Fiachra, and Conn. After their mother died, Lir married her sister, Aoife. Jealous of Lir's love for his children, Aoife used her magic to turn them into swans.
She cursed them to spend 900 years on the waters of Ireland: 300 years on Lake Derravaragh, 300 years on the Sea of Moyle, and 300 years on the Atlantic near Inishglora. However, she allowed them to keep their human voices and the ability to sing the most beautiful music ever heard.
After 900 years, the spell was finally broken when they heard the bell of a Christian monk (St. Patrick or St. Mo Chua). They returned to human form but were incredibly old and frail. They were baptized just before they died, finding peace at last.