Soteria, (from Greek: “deliverance”), in Hellenistic religions, any sacrifice or series of sacrifices performed either in commemoration or in expectation of deliverance from a crisis; in a specific sense the word was often used in reference to large-scale commemorative festivals held at planned intervals. Sixteen Soteria festivals are known; the most famous was that at Delphi, which celebrated the defeat of the Celts in 279–278 bc.