Once upon a time, there was a man named Lir. He lived in a kingdom and its king was King Bodb Derg, much to the annoyance of Lir who was the God of the Sea. To please Lir, Bodb gave Lir one of his daughters, Aiobhto for him to marry. They gave birth to a girl called Fionnula, twins called Fiachra and Conn(boys) and a son named Aodh.
Aoibh died, much to the sadness of her childrden. Bodb, to keep Lir happy gave another daughter for marriage, Aoife. But Aoife was jealous of the Childrens love for another and their father, Aoife plotted to get rid of them. She ordered her servant to kill them on the way to Bobd's house but the servant refused. She attemted to kill them herself but could not bring herself to do it.
So when they reached a lake she told them to swim if they like, and being the son of the god of the sea they swam with grace. And Aoife (having magic herself) canted an incantation and a mist befall the children as they became swans.
"Haha!" Laughed Aoife. "I have turned you to swans. You no longer look like humans anymore! To turn back to yourselves you must spend 300 years in Lough Derravagh, 300 years in the Sea of Moyle, and then another 300 years in Irrus Domnann. After that you must hear the bell of a monk!"
"You won't get away with this!" the children cried. They found out they may be swans but they can talk. So they flew back to their father and said what Aoife had done. Aoife was then excecuted for the crime.
They knew what to do. Time passed by and when the 900 years were up they went back to where their kingdom was. Unfortunately the land was destroyed. They went back and saw a man named Machua, a monk, and then they asked if he could ring the bell. They found that the man knew of them, from little tales he had heard.
And another disaster struck. A prince came and demanded that he have the swans. They had to go with him and Machua rang the bell. The children then became young but then aged. So he baptised them as they aged and finally passed away. Around the time St.Patrick (Irelands Patron Saint) had spread Christianity through Ireland. The children passed away, now just a simple legend.