Apollo's usual myths are stories of a god acting from strength: slaying Python, founding an oracle. Apollodorus's Library preserves an episode that runs the other way. When Zeus killed Apollo's mortal son Asclepius with a thunderbolt, fearing that Asclepius's skill at reviving the dead would make mortals immortal, Apollo could not strike back at Zeus himself, so he killed the Cyclopes who had forged the bolt instead. Zeus's punishment was to sentence Apollo to a year serving a mortal master, and Apollo was bound over as herdsman to Admetus, king of Pherae in Thessaly, forbidden the use of his own power for the length of his service. Admetus treated the god well, and when the year ended Apollo repaid him: Admetus was courting Alcestis, daughter of King Pelias, who had set an impossible bride price, a chariot yoked with a lion and a boar together, and Apollo used his divine strength to yoke the two beasts himself, letting Admetus present them and win Alcestis's hand. Apollo went further still, persuading the Fates to grant Admetus release from his own appointed death if another could be found to die in his place, the bargain that becomes the subject of Euripides's Alcestis. A god's servitude, in this telling, is the origin of a mortal marriage the stage would go on to make famous.