In Greek mythology, Iasion (also Iasus or Eetion) was a Samothracian hero, son of Zeus and the Pleiad Electra, and brother of Dardanus. He lay with Demeter in a thrice-ploughed field and fathered Plutus; most traditions say Zeus then slew him with a thunderbolt. He is distinct from the Arcadian Iasus (father of Atalanta) and other homonyms named Iasus or Iasius.
Adapted from Wikipedia, "Iasion" · CC BY-SA 4.0
I.Family
Apollodorus, Hellanicus, and Diodorus make Iasion the son of Electra (daughter of Atlas) and Zeus, and brother of Dardanus; some notices add Harmonia or Emathion as siblings. An Italian genealogical strand places the brothers' births in Italy, with Corythus as Iasion's father. Hyginus once calls him son of Ilithyius.
With Demeter he is father of Plutus, the god of agricultural wealth (Hesiod, Theogony). Hyginus' De astronomia also gives him Philomelus; Diodorus names a son Corybas by Cybele.
II.Mythology
Homer and Hesiod place the union of Demeter and Iasion in a thrice-ploughed fallow; Zeus learns of it and strikes Iasion with a thunderbolt. Apollodorus frames the act as an assault on the goddess and has Dardanus leave Samothrace in grief. A Cadmus–Harmonia wedding variant has Demeter lure Iasion from the feast into a freshly ploughed furrow; Zeus reads the mud on her dress and kills him out of envy.
Rival endings survive: Servius has Dardanus kill his brother; Hyginus attributes the death to horses; Ovid instead lets Iasion live to old age as Demeter's husband. Some late notices connect Iasion and Triptolemus with the constellation Gemini. He is remembered as a founder of Samothracian mystic rites.
III.Homonyms
Iasion/Iasus/Iasius is a crowded name-set. The Samothracian lover of Demeter must not be merged with the Arcadian Iasus (father of Atalanta), the Argive Iasus (connected with Io), or Homeric Athenians and Cypriots who share the name. This atlas node is the Samothracian hero alone.