Athamas was the mythological king of the Greek city of Orchomenus. He had four children: Phrixus and Helle with his first wife Nephele, and Learches and Melicertes with Ino.
Through the machinations of the latter, Athamas was persuaded to sacrifice Phrixus and Helle to save Orchomenus from drought. Nephele, however, sent a flying golden ram to rescue her children. Phrixus was indeed saved, but Helle died after falling off the ram into the Hellespont.
Following this Athamas fled to Thessaly, where he took Themisto as his third wife.