One of the great Romantic legends of Ireland is that of Diarmuid & Grainne,
Grainne, was the most beautiful woman in Ireland, she was also the daughter of Cormac MacAirt, the High King of Ireland. Grainne was courted by Ireland's most eligible, Princes and Chieftains, including the now ageing chief Fionn MacCool.
Irish Mythology - Mythical Cycle - Book of Invasions