Admetus (Greek: Ἄδμητος) was the king of Pherae in the region of Thessaly, son of Pheres. He participated in the Argonautic Expedition.
Admetus and Apollo
He was a fair and hospitable king; when Apollo was forced to serve under a mortal because of killing Delphine, he chose to serve as Admetus’ herdsman. Apollo in recompense for Admetus' treatment made all the cows bear twins while he served as his cowherd.
Apollo also helped Admetus win the hand of Alcestis, the daughter of Pelias, king of Iolcus. Alcestis had so many suitors that Pelias set an apparently impossible task to the suitors—to win the hand of Alcestis, they must yoke a boar and a lion to a chariot. Apollo harnessed the yoke with the animals and Admetus drove the chariot to Pelias, and thus married Alcestis.
Admetus, however, neglected to sacrifice to Artemis, Apollo's sister. The offended goddess filled the bridal chamber with snakes and again, Apollo came to Admetus' aid. Apollo advised Admetus to sacrifice to Artemis, and the goddess removed the snakes.
The greatest aid Apollo gave to Admetus was persuading the Fates to reprieve Admetus of his fated day of death. When the Fates decided it was time for Admetus to die, Apollo intoxicated them with wine and made them agree to reprieve him as long as someone else would take his place. Admetus initially believed that one of his aged parents would happily take their son's place of death. When they were unwilling, Alcestis instead agreed to take her husband's place and was escorted by Thanatos, god of death, to the Underworld. Later, when Heracles had undertaken the Twelve Labours, Admetus treated him very kindly; the demigod repaid for Admetus’ hospitality, by going to the Underworld and fighting with Thanatos. Thus, he managed to bring Alcestis back from the dead to her husband.