also called USIRI, one of the most important gods of ancient Egypt. The origin of Osiris is obscure; he was a local god of Busiris, in Lower Egypt, and may have been a personification of chthonic (underworld) fertility, or possibly a deified hero. By about 2400 BC, however, Osiris clearly played a double role: he was both a god of fertility and the embodiment of the dead and resurrected king. This dual role was in turn combined with the Egyptian concept of divine kingship: the king at death became Osiris, god of the underworld; and the dead king's son, the living king, was identified with Horus, a god of the sky. Osiris and Horus were thus father and son. The goddess Isis was the mother of the king and was thus the mother of Horus and consort of Osiris. The god Seth was considered the murderer of Osiris and adversary of Horus.

    According to the form of the myth reported by the Greek author Plutarch, Osiris was slain or drowned by Seth, who tore the corpse into 14 pieces and flung them over Egypt. Eventually, Isis and her sister Nephthys found and buried all the pieces, except the phallus, thereby giving new life to Osiris, who thenceforth remained in the underworld as ruler and judge. Isis revived Osiris by magical means and conceived her son Horus by him. Horus later successfully fought against Seth and became the new king of Egypt.

    Osiris was not only ruler of the dead but also the power that granted all life from the underworld, from sprouting vegetation to the annual flood of the Nile. From about 2000 BC onward it was believed that every man, not just the deceased kings, became associated with Osiris at death. This identification with Osiris, however, did not imply resurrection, for even Osiris did not rise from the dead. Instead, it signified the renewal of life both in the next world and through one's descendants on Earth. In this universalized form Osiris' cult spread throughout Egypt, often joining with the cults of local fertility and underworld deities.