Euhemerus (yo͞ohĕm`ərəs), fl. c.300 B.C., Cyrenaic philosopher, b. Sicily. He is famous for a theory of mythology embodied in his philosophical romance, Sacred History, a work of which only fragments remain. Euhemerus' theory, called after him euhemerism, was that the gods originated from the elaboration of traditions of distinguished historical persons. His theory was consistent with the attempts of his period to explain religious beliefs in terms of naturalism.