In Greek mythology, Stheno was one of the three sister Gorgons, the others being Euryale and Medusa, monstrous beings whose gaze turned onlookers to stone. Together with Euryale, Stheno was immortal, while their sister Medusa alone was mortal. When the hero Perseus beheaded Medusa, Stheno and Euryale pursued him but were unable to catch him. Her name derives from the Ancient Greek Sthenō, meaning "forceful."
Adapted from Wikipedia, "Stheno and Euryale" · CC BY-SA 4.0
I.Family
According to Hesiod and Apollodorus, Stheno and Euryale, along with their sister Medusa, were daughters of the primordial sea-god Phorcys and the sea-monster Ceto.
Hyginus, however, presents an alternative and textually corrupt genealogy, naming the Gorgons as offspring of "the Gorgon" (an offspring of Typhon and Echidna) and Ceto.
II.Mythology
The Gorgons Stheno and Euryale were immortal, whereas their sister Medusa was mortal. The only story that involves them is their pursuit of Perseus after he had beheaded Medusa.
The Hesiodic Shield of Heracles describes the pursuit, depicting the two Gorgons on Heracles' shield as rushing after Perseus. According to Apollodorus, when Perseus beheaded Medusa using her reflection in his bronze shield, Stheno and Euryale chased him but could not see him because he wore Hades' cap of invisibility.
The poet Pindar describes both Gorgons as possessing "horrible snakey hair." Euryale's lamenting cry during the chase is noted in classical sources: Pindar tells how Athena created flute songs to imitate her "shrill cry," while Nonnus describes Perseus "listening for no trumpet but Euryale's bellowing."
III.Iconography
The typical archaic depictions of Stheno and Euryale (c. 8th–5th century BC) show the head turned to face the viewer, sitting (seemingly without a neck) atop a running body shown in profile, with wings on the back and curl-topped boots.
In later depictions the heads shrink in size relative to their bodies, gain necks, and become less wild looking.