Ahh, you know what? I found my Encyclopedia of Celtic Mythology and Folklore. Here’s what it has to say about Aine!
Áine (Enya)
Irish goddess, heroine or spirit. Irish legend offers several figures of this name, which means “brightness” or “splendor”. Historical figures of this name tend to be male and are connected with the Limerick/north Kerry area of the southwestern province of Munster; mythological figures are female and are typically connected to the same area, although the name is found as far away as Ulster. The most prominent Áines of myth may be ultimately the same or may derive from the same original.
Áine of Knockainy [Cnoc Áine], usually described as a fiary queen although she is probably a diminshed goddess, who inhabits a hill near storied Lough Gur in east Co. Limerick. Several scholars connect her with Anu (Danu), the great goddess of Munster who have her name to the Tuatha Dé Danann, the tribe of the goddess Danu.
There are indications that she was a sun goddess, for she was connected with solar wells like Tobar Áine near Lissan in Ulster as well as being linked with the sun goddess Grian, her sister; but at other times she is described as related to Finnen, “white,” an obscure goddess of the Lough Gur region. As sun goddess, Áine could assume the form of an unbeatable horse, Lair Derg (“red mare”).
Áine’s special feast was held on either midsummer night, the summer solstice on June 21, or on Lughnasa, the Celtic feast on August 1. At that time, straw torches were waved over animals that were then driven up the slopes of Knockainy to solicit Áine’s protection. She is sometimes called Áine Chlair, either from the connection with the “cliars” or torches used in such ceremonies, or from Cliu/Cliach, the ancient name for the territory. “The best-hearted woman that ever lived,” as she was locally called, was reported to have been seen on the slopes of her mountain even into recent times, offering help to those in need.
The long list of Áine’s lovers includes both gods and mortals. Among the former was the sea god Manannán Mac Lir. Áine’s brother Ailléen fell in love with Manannán’s wife, and Manannán with Áine, so Manannán gave his wife to Ailléen in exchange for the charms of Áine. (A varient has Áine as daughter rather than lover to Manannán.) Although a lustful goddess, she also has a matronly aspect, for her “birth chair” can be seen on the mountain Knockadoon.
Áine was the lover of Maurice (Muiris), the human Earl of Desmond, who stole her cloak in order to capture her; once captured, she bore him a son, Geróid Iarla or Gerald the waterbird. Warned against showing any surprise at their magical son’s behavior, Maurice remained composed at all times – until Geróid was fully grown and showed himself able to shrink almost into invisibility at will. When his father called out in astomishment, Geróid disappeared; he is said to live still in Lough Gur and to ride around it every seven years on a white horse. The descendants of Áine’s son – the Geraldines or Fitzgeralds – long claimed sovereignty in western Munster through this descent from the goddess of the land.
Áine did not always go willingly to prospective lovers; she was responsible for the death of the hero Étar, who expired of a broken heart when she rejected him. She was also said to have resisted Ailill Olom, who took her against her will and whose ear she ripped off in her unsuccessful fight against him; the child of the rape was Eógan, a story that some scholars describe as an invention of his descendants, the Eóganacht rulers, to affirm control of the lands under Áine’s sovereignty.
Some legends connect Áine with madness, for those who sat on her stone chair went mad, and if they sat there three times, they would never recover their wits. Those who were already mad, however, could regain their sanity through the same process.
Áine of Donegal, from the parish of Teelin in the townland of Cruachlann, near another mountain called Cnoc Áine; there Áine was said to have been a human woman who disappeared into the mountain to escape a savage father. She now spends her time spinning sunbeams, this story says, suggesting that the folkloric figure disguises an ancient sun goddess. A folk verse from the area has Áine telling discontented wives how to weaken their husbands with “corn warm from the kiln and sheep’s milk on the boil.”
Áine of the Fenian Cycle, daughter of either the fairy king Cuilenn or a Scottish king, was the lover of Fionn Mac Cumhail, by whom she had two sons. Áine and her sister Milucra fought for Fiann’s affections; Milucra turned him into a graybeareded ancient who would be uncomplelled by lust, but Áine restored him to youth with a magical drink. Fionn, however, married neither of the sisters.
The Encyclopedia of Celtic Mythology and Folklore by Patricia Monaghan