And if any one would sit on that stone he would be in danger of losing his wits, and any one that would sit on it three times would lose them for ever. And people whose wits were astray would make their way to it, and mad dogs would come from all parts of the country, and would flock around it, and then they would go into the sea to Áine's place there.
But those that did cures by herbs said she had power over the whole
And Ailill's son was passing the river with his step-brother, and they saw the tree and heard the sweet music from it. And first they quarreled as to which of them would have the little harper, and then they quarreled about the tree, and they asked a judgment from Ailill, and he gave it for his own son. And it was the bad feeling about that judgment that led to the battle of Magh Mucraime, and Ailill and his seven sons were killed there, and so Aine got her revenge.
And this is how the event came about; one Samhain Ailill Olom went to graze his cattle on the hill of Knockainy (Áine's hill) and that night the hill was stripped clean of all the grass that grew on it and when this happened three times the king knew that it was due to magic of some sort and he sent for the warrior-druid Ferches who lived in Leinster. Ferches came to the king on the following Samhain and they both went to the hill where the king slept while Ferches kept watch.
As he waited the people of the fairy hill came out and they were followed by their king Eoghanach and his daughter Áine who carried and played a timpán of copper. Ferches rose and aimed a blow at him but Áine's father turned and ran back to enter the Sidhe. As he ran Ferches struck him with a javelin and piercing him through broke his back. Ailill Olom caught the girl and possessed her but Áine struggled with him and in the struggle she bit off his ear. Ever after he was known as 'Bare Ear'. And Áine swore revenge on him saying:
'Ill have you been to me, to have done me violence and to have killed my father. To requite this I too will do thee violence and by the time we two shall have done with one another I will leave thee wanting all means of reprisal.'
source Lady Gregory - Gods and Fighting Men