1911 Encyclopædia Britannica/Alcestis
ALCESTIS (Alkestis), in Greek legend the daughter of Pelias and Anaxibia, and wife of Admetus, king of Pherae in Thessaly. She consented to die in place of her husband, and was afterwards rescued by Heracles. This beautiful story of conjugal devotion forms the subject of the Alcestis of Euripides, which furnished the basis of Robert Browning’s Balaustion’s Adventure. Sophocles also wrote an Alcestis, of which only fragments remain.
See Dissel, Der Mythos von Admetus und Alkestis, 1882.