Ilissos in the Greek Mythology
Ilissos was a River-God of Attika. His parents are considered to be Okeanos and Tethys and Plato in Phaedrus mentions that his offspring is Pharmakeia. The stream of the river Ilissos flowed through the town of Athens.
"Phaidros: I should like to know, Sokrates, whether the place is not somewhere here at which Boreas is said to have carried off Oreithyia from the banks of the Ilissos?
Socrates: Such is the tradition.
Phaidros: And is this the exact spot? The little stream [the Ilissos] is delightfully clear and bright; I can fancy that there might be maidens playing near.
Socrates: I believe that the spot is not exactly here, but about a quarter of a mile lower down, where you cross to the temple of Artemis, and there is, I think, some sort of an altar of Boreas at the place ...Oreithyia was playing with Pharmakeia [presumably the Naiad daughter of Ilissos], when a northern gust carried her over the neighbouring rocks; and this being the manner of her death, she was said to have been carried away by Boreas."
Plato, Phaedrus 229