Thetis and Peleus.
Thetis was courted by two Olympian gods, Zeus (Jupiter) and Poseidon (Neptune). However, when the gods learned from Prometheus (or the oracle of Themis) that she was destined to bear a son who would eclipse the power of his father, they abandoned their suit and betrothed her to the mortal Peleus, king of the Phthians. When Peleus attempted to claim his prize, Thetis tried to elude him by transforming herself—into fire, water, and various beasts—but Peleus held her tightly and eventually she agreed to marry him.
      Their marriage took place on Mount Pelion, home of the centaur Chiron. All the gods except Eris, goddess of Discord, attended and presented gifts that included a spear from Chiron and two immortal horses, Xanthus and Balius, from Poseidon. Eris, who had not been invited, appeared and spitefully threw a golden apple among the goddesses, inscribed “to the fairest.” This set off a dispute among Hera (Juno), Athena (Minerva), and Aphrodite (Venus) for possession of the apple, thus setting the stage for the Judgment of Paris and the Trojan War. Thetis and Peleus separated after the birth of their son, Achilles, when Thetis tried to make him immortal.
       The wedding feast of Peleus and Thetis was a common theme for classical black- and red-figure vase painters and continued to be favored by post-classical artists.
      
       Classical Sources. Homer, Iliad 1.351—457,18.35—147- Pindar, Isthmian Odes 8. Euripides, Iphigenia in Aulis 700-07, 1036—47. Catullus, Carmina 64. Ovid, Metamorphoses 11.215-66. Apollodorus, Biblioteca 3.13.4-5, E3.2. Hyginus, Fabulae 54. Lucian, Dialogues of the Sea Gods 7, “Panope and Galene.”