Stheno was the eldest of the three Gorgon sisters — and, the myths say, the deadliest of them all, having killed more men than both her sisters combined. Yet she is forever overshadowed by her younger, mortal sister Medusa, because Stheno had something Medusa lacked: she was immortal, and so no hero ever defeated her.
The Eldest Gorgon
Stheno (whose name means “strength” or “the mighty”) was one of three monstrous sisters, the Gorgons, daughters of the ancient sea-deities Phorcys and Ceto. Like her sisters Euryale and Medusa, she was a winged creature with serpents for hair, fearsome tusks, and a gaze that turned the living to stone. But where Medusa was mortal, Stheno and Euryale were immortal and ageless — eternal monsters who could never be slain.
The Deadliest of the Three
Ancient sources record that Stheno was the most ferocious and independent of the Gorgons, said to have slain more men than her two sisters put together. Fierce, violent, and undying, she dwelt with her sisters at the edge of the world, a terror to any who approached.
The Sister Who Could Not Be Killed
When the hero Perseus came to behead a Gorgon, he could target only one: Medusa, the sole mortal sister. He beheaded her using a mirror-shield to avoid her gaze — but he had to flee immediately, because the immortal Stheno and Euryale woke, saw their sister slain, and pursued him in a fury. Only Perseus's winged sandals and cap of invisibility allowed him to escape the two undying sisters, who could never themselves be killed. Stheno's grief and rage went unavenged, for there was no weapon in the cosmos that could end her.
The Forgotten Terror
Stheno endures as a reminder that Medusa was not alone — that she was the youngest and only vulnerable of three monstrous sisters, and that the most dangerous Gorgon of all was the one no hero could touch. Stheno is the eternal, undefeated monster: the terror that outlived the famous victory, still dwelling, immortal, at the edge of the world.
Medusa was the one who could die — her eldest sister was the one who never could.