Definition: Alcestis was the noble wife of King Admetus of Thessaly. When Admetus was told he would die unless someone else took his place, no one he asked volunteered, including his aged parents. At last Alcestis volunteered, Admetus accepted, and then Alcestis sacrificed herself. When Hercules arrived at the home of the king of Thessaly, he didn't know what had happened to cause the sorrow. Admetus, downplaying the situation, told the hero that someone had died, but she was not a member of the family. When Hercules learned of Alcestis' death from the servants, he rescued Alcestis from Hades. This is the subject of Euripides' Alcestis tragedy and one of the occasions on which Hercules successfully ventured into the Underworld.