Caer Ibormeith, Irish Goddess of sleep and dreams, and perhaps a less violent version of Mare. She was a daughter of a faery king, Ethal Anbuail, of Sid Uamuin in Connacht. She wore a copious golden chain with 130 golden balls on a silver chain about her slender neck.
Every alternate Samhain she would change into a swan on a lake called Dragonís Mouth. In this form she would remain for a year before becoming human again the following Samhain.
She eventually married Aengus of the Tuatha de Dannan, but first he had to pick her out, in swan form, from a group of one hundred and fifty other swans at Loch Bel Dragon. Having chosen correctly, he turned into a swan himself and they flew away to the fortress of the River Boyne at Drogheda, singing beautiful music that put all its listeners asleep for three days and nights. With Aengus, Caer was the foster-mother of Diarmuid.