Greco-Roman era Hellenization thumb|upright|Bust of Serapis. The early Ptolemaic kings promoted a new god, Serapis, who combined traits of Osiris with those of various Greek gods and was portrayed in a Hellenistic form. Serapis was often treated as the consort of Isis and became the patron deity of the Ptolemies' capital, Alexandria. Serapis's origins are not known. Some ancient authors claim the cult of Serapis was established at Alexandria by Alexander the Great himself, but most who discuss the subject of Serapis's origins give a story similar to that by Plutarch. Writing about 400 years after the fact, Plutarch claimed that Ptolemy I established the cult after dreaming of a colossal statue at Sinope in Anatolia. His councillors identified the statue as the Greek god Pluto and said that the Egyptian name for Pluto was Serapis. This name may have been a Hellenization of "Osiris-Apis".Françoise Dunand and Christiane Zivie-Coche (2004), Gods and Men in Egypt: 3000 BCE to 395 CE, pp. 214–215 Osiris-Apis was a patron deity of the Memphite Necropolis and the father of the Apis bull who was worshipped there, and texts from Ptolemaic times treat "Serapis" as the Greek translation of "Osiris-Apis". But little of the early evidence for Serapis's cult comes from Memphis, and much of it comes from the Mediterranean world with no reference to an Egyptian origin for Serapis, so Mark Smith expresses doubt that Serapis originated as a Greek form of Osiris-Apis's name and leaves open the possibility that Serapis originated outside Egypt.
Greco-Roman era Hellenization thumb|upright|Bust of Serapis. The early Ptolemaic kings promoted a new god, Serapis, who combined traits of Osiris with those of various Greek gods and was portrayed in a Hellenistic form. Serapis was often treated as the consort of Isis and became the patron deity of the Ptolemies' capital, Alexandria. Serapis's origins are not known. Some ancient authors claim the cult of Serapis was established at Alexandria by Alexander the Great himself but most who discuss the subject of Serapis's origins give a story similar to that by Plutarch. Writing about 400 years after the fact, Plutarch claimed that Ptolemy I established the cult after dreaming of a colossal statue at Sinope in Anatolia. His councillors identified the statue as the Greek god Pluto and said that the Egyptian name for Pluto was Serapis. This name may have been a Hellenization of "Osiris-Apis".Françoise Dunand and Christiane Zivie-Coche (2004), Gods and Men in Egypt: 3000 BCE to 395 CE, pp. 214–215 Osiris-Apis was a patron deity of the Memphite Necropolis and the father of the Apis bull ,who was worshipped there, and texts from Ptolemaic times treat "Serapis" as the Greek translation of "Osiris-Apis". But little of the early evidence for Serapis's cult comes from Memphis, and much of it comes from the Mediterranean world with no reference to an Egyptian origin for Serapis, so Mark Smith expresses doubt that Serapis originated as a Greek form of Osiris-Apis's name and leaves open the possibility that Serapis originated outside Egypt.