In Greek mythology, Rhadamanthus (Ῥαδάμανθυς; also transliterated as Rhadamanthys or Rhadamanthos) was a wise king, the son of Zeus andEuropa. Later accounts even make him out to be one of the judges of the dead. His brothers were Sarpedon and Minos (also a king and later a judge of the dead). Rhadamanthus was raised by Asterion. He had two sons, Gortys and Erythrus. Other sources (e.g., Plutarch; Thes. 20) credit Rhadamanthys rather than Dionysus as the husband of Ariadne, and the father of Oenopion, Staphylus and Thoas. In this account, Ariadne was the daughter King Minos, Rhadamanthys' brother; another Ariadne was the daughter of Minos' grandson and namesake, who features in the Theseus legend, and was rescued by Dionysus.
Driven out of Crete by his brother, Minos, who was jealous of his popularity, he fled to Boeotia, where he wedded Alcmene. Homer represents him as dwelling in the Elysian Fields (Odyssey, iv. 564), the paradise for the immortal sons of Zeus.
According to later legends (c. 400 BC), on account of his inflexible integrity he was made one of the judges of the dead in the lower world, together with Aeacus and Minos. He was supposed to judge the souls of easterners, Aeacus those of westerners, while Minos had the casting vote (Plato, Gorgias, 524A).