Plutarch, De Iside et Osiride
Frank Cole Babbitt, Ed.

Ptolemy Soter saw in a dream the colossal statue of Pluto in Sinope, not knowing nor having ever seen how it looked, and in his dream the statue bade him convey it with all speed to Alexandria. He had no information and no means of knowing where the statue was situated, but as he related the vision to his friends there was discovered for him a much travelled man by the name of Sosibius, who said that [p. 69] he had seen in Sinopê just such a great statue as the king thought he saw. Ptolemy, therefore, sent Soteles and Dionysius, who, after a considerable time and with great difficulty, and not without the help of divine providence, succeeded in stealing the statue and bringing it away.¹ When it had been conveyed to Egypt and exposed to view, Timotheus, the expositor of sacred law, and Manetho of Sebennytus, and their associates, conjectured that it was the statue of Pluto, basing their conjecture on the Cerberus and the serpent with it, and they convinced Ptolemy that it was the statue of none other of the gods but Serapis. It certainly did not bear this name when it came from Sinope, but, after it had been conveyed to Alexandria, it took to itself the name which Pluto bears among the Egyptians, that of Serapis. Moreover, since Heracleitus² the physical philosopher says, ‘The same are Hades and Dionysus, to honour whom they rage and rave,’ people are inclined to come to this opinion. In fact, those who insist that the body is called Hades, since the soul is, as it were, deranged and inebriate when it is in the body, are too frivolous in their use of allegory. It is better to identify Osiris with Dionysus³ and Serapis with Osiris,⁴ who received this appellation at the time when he changed his nature. For this reason Serapis is a god of all peoples in common, even as Osiris is ; and this they who have participated in the holy rites well know. [p. 71]