Seneca’s Thyestes is based on an old Greek myth from the collection of traditions involving the family of Tantalus and the royal house of Mycenae or Argos (after Homer, the two city-states were often regarded as interchangeable in literature). Tantalus, the sinful patriarch, was a son of Zeus (Jupiter to the Romans) notorious for killing his son Pelops and serving him to the gods to test their divinity. The gods saw through this trick and punished Tantalus for his impiety, casting him into the underworld to suffer an eternal “tantalizing” torment: In what became the best-known version of the myth, this torment involved unquenchable hunger and thirst, though other versions substituted this with a large boulder forever suspended over Tantalus’s head, threatening to fall at any moment.

Tantalus’s son Pelops, meanwhile, was brought back to life. He traveled to Greece, where he sought to marry Hippodamia, daughter of the Pisan king Oenomaus. Oenomaus challenged all his daughter’s suitors to a chariot race and beat them all with the help of his divine horses. Pelops paid off Oenomaus’s charioteer Myrtilus to rig the race by sabotaging the king’s chariot. During the race, Oenomaus was killed, and Pelops won Hippodamia and the throne of Pisa; he rewarded Myrtilus by casting him into the sea.