Brief History of ALCESTIS and its meaning.

Asklepios, the son of Apollo, was endowed by his father with such skill in the healing art that he even restored the dead to life. At this, Hades took alarm and prevailed on Zeus to launch a thunderbolt at Asklepios. Apollo was indignant at the destruction of his son and wreaked his vengeance on the innocent workmen who had made the thunderbolt. These were the Cyclopes, who have their workshop under Mount Aetna, from which the smoke and flames of their furnaces are constantly issuing. Apollo shot his arrows at the Cyclopes, which so incensed Zeus that he condemned him as a punishment to become the servant to a mortal for the space of one year. Accordingly Apollo went into the service of Admetus, King of Thessaly, and pastured his flocks for him on the verdant banks of the River Amphrysos.

Admetus was a suitor, with others, for the hand of Alcestis, the daughter of Pelias, who promised her to him who should come for her in a chariot drawn by lions and boars. This task Admetus performed by the assistance of his divine herdsman, and was made happy in the possession of Alcestis. But Admetus fell ill, and being near to death, Apollo prevailed on the Fates to spare him on condition that someone would consent to die in his stead. Admetus, in his joy at this reprieve, thought little of the ransom, and perhaps remembering the declarations of attachment which he had often heard from his courtiers and dependents, fancied that it would be easy to find a substitute. But it was not so. Brave warriors, who would willingly have periled their lives for their prince, shrunk from the thought of dying for him on the bed of sickness; and old servants who had experienced his bounty and that of his house from their childhood up were not willing to lay down the scanty remnant of their days to show their gratitude.

Men asked, "Why does not one of his parents do it? They cannot in the course of nature live much longer, and who can feel like them the call to rescue the life they gave, from an untimely end?" But the parents, distressed though they were at the thought of losing him, shrunk from the call. Then Alcestis, with a generous self-devotion, proffered herself as the substitute. Admetus, fond as he was of life, would not have submitted to receive it at such a cost; but there was no remedy. The condition imposed by the Fates had been met, and the decree was irrevocable. Alcestis sickened as Admetus revived, and she was rapidly sinking to the grave.

from Bulfinch's Mythology