The Wedding of Peleus and Thetis and the Apple of Discord
Also called: Apple of Discord, Golden apple of Eris
A legend handed down over the centuries.
A Greek myth told in the epic Cypria and later mythographers. Eris, goddess of strife, left out of the wedding feast of the hero Peleus and the sea goddess Thetis, threw in a golden apple inscribed “to the fairest”, setting Hera, Athena and Aphrodite against one another.

Jacob Jordaens / After Peter Paul Rubens / Peter Paul Rubens · Public domain · Source
This Greek myth is told in the Cypria, an epic on the events before the Trojan War (c. 7th–6th century BC, surviving only in fragments and a later summary), and in mythographers such as Apollodorus. Because of a prophecy that the sea goddess Thetis would bear a son greater than his father, Zeus kept away from her and gave her in marriage to the mortal hero Peleus. All the gods came to the wedding feast on Mount Pelion except Eris, goddess of strife, who had not been invited. She appeared and stirred up a quarrel, and Hera, Athena and Aphrodite fell to disputing which of them was the most beautiful.
The golden apple inscribed “to the fairest” appears in later writers such as Hyginus (Fabulae) and Lucian. A surviving fragment of the Cypria also says that Zeus planned the Trojan War to relieve the earth of its burden of too many people. The son born of this marriage was Achilles, hero of the Iliad. “Apple of discord” is still used for the seed of a quarrel.