Io: Leaping in torments of hunger I come
With a furious rush, the victim
Of the cunning and jealousy of Hera
Suffers what I suffer?
~But mark out clearly
The Fate that will be mine in time
To come; what remedy, what medicine for ill?
Tell me, if you know them:
Speak to the virgin who wanders in misery? 
~ Prometheus Bound: 600 ~ Aeschylus

“According to a legend preserved in Aeschylus’s Prometheus Bound, the tormented nymph Io, when released from Argus by Hermis, fled, in the form of a cow, to Egypt; and there, according to a later legend, recovering her human form, gave birth to a son identified as Serapis, and Io became known as the goddess Isis.” Pg. 250-251, Goddesses~ Joseph Campbell