The three daughters of Phorcus and Ceta, sisters of the Gorgons and other monsters. They were believed to be the personifications of the white foam on the sea.
The Graeae were born as old women, and during their existence they kept growing older. They only had one eye and one tooth that they shared between them.
Perseus took their eye, which they used for guarding the Gorgons, in order to find out where the nymphs that would help him were. He had promised the old women to give them their eye back if they gave him the information they needed, but did not keep his promise and threw the eye into lake Triton.
Io also met them while she was trying to escape the wrath of Hera.