The Gorgons were three sisters in early Greek poetry: Stheno, Euryale, and Medusa. Hesiod describes Medusa as mortal and the other two as deathless. Later art and literature expanded their appearance, powers, and relationship with heroes and gods.
Medusa and her sisters
Hesiod places the Gorgons beyond Ocean near the region of Night. Perseus kills Medusa while guided by divine helpers. When her head is cut off, Pegasus and Chrysaor spring from her body because she had conceived them by Poseidon.
The power to turn viewers to stone becomes central in later accounts. Perseus uses the severed head as a weapon and eventually gives it to Athena, who places the gorgoneion on her protective equipment.
Changing image
Archaic Greek art often gives Gorgons broad faces, tusks, protruding tongues, and staring eyes. Snake hair becomes increasingly prominent, while later artists sometimes make Medusa beautiful as well as dangerous.
Ovid’s Roman poem tells a later story in which Neptune violates Medusa in Minerva’s temple and Minerva transforms her hair. That influential version should not be presented as the only or earliest Greek account. Ancient sources disagree, and many do not describe a transformation at all.