Rarus was a son of Cranaus and eponym of the Rharian Field near Eleusis, where the first plot of grain was grown after Demeter taught humanity the secrets of agriculture. Choerilus, an Athenian who wrote a play called Alope claimed that Rarus was the father of Triptolemus by an unnamed daughter of Amphictyon, a king of Athens. According to a different mythological tradition, Rarus was the father of Celeus and the grandfather of Triptolemus. When Demeter arrived at his place, during her search for Persephone, Rarus welcomed the goddess and offered her hospitality. As an expression of her gratitude, Demeter taught his grandson the art of cultivating grain.