Áine, daughter of either the #fairy king Cuilenn or a #Scottish king, was the lover of #FionnMacCumhail, by whom she had two sons. Áine and her sister #Milucra fought for Fionn’s affections. Milucra turned him into a graybearded ancient who would be uncompelled by lust, but Áine restored him to youth with a magical drink. Fionn, however, married neither of the sisters.
Source: P. Monaghan `Encyclopedia of #Celtic #Mythology and #Folklore`