Pluto and Hades differ in character, but they are not distinct figures and share two dominant myths. In Greek cosmogony, the god received the rule of the underworld in a three-way division of sovereignty over the world, with his brother Zeus ruling the sky and his other brother Poseidon sovereign over the sea. His central narrative in myth is of him abducting Persephone to be his wife and the queen of his realm. "Plouton" as the name of the ruler of the underworld first appears in Greek literature of the Classical period, in the works of the Athenian playwrights and of the philosopher Plato, who is the major Greek source on its significance. Under the name Pluto, the god appears in other myths in a secondary role, mostly as the possessor of a quest-object, and especially in the descent of Orpheus or other heroes to the underworld.