Celeus, in Greek mythology, was the king of the area of Eleusis and husband of Metaneira. He was also one of the first priests of the goddess of agriculture, Demeter, who also established the cult of the Eleusinian Mysteries.
After Persephone, Demeter's daughter, was abducted by Hades, Demeter started looking for her and stopped at Celeus' palace. Transformed into an old woman, she was warmly treated by Celeus, who asked her to nurse his son, Demophon. To thank Celeus for his kindness and hospitality, Demeter decided to secretly immortalise Demophon by burning away his mortal body in the flames of the hearth. However, she was found out by Metaneira, who started screaming and angered the goddess. So, Demeter decided instead to teach Demophon's brother Triptolemus, the art of agriculture, who later taught it to all Greeks.