The god Serapis was probably first introduced in Egypt by Alexander, although it was Alexander’s successor Ptolemy I (r. 323-283 BCE) who helped popularize the god there by bringing the god’s statue from Sinope (a city on the Black Sea in present-day Turkey, east of Istanbul) to Alexandria, where Greeks were beginning to settle. Ptolemy also established the Alexandrian library and the world’s first university with a medical school. (Segerberg, p. 99)
Legend holds that Ptolemy told his advisor — Timotheos of Eleusis, or, "the Eumolpid" (Rose, p. 108; Cumont, p. 51) — that he dreamed of a statue with a serpent at its feet — the serpent having three heads of dog, wolf, and lion — and a corn measuring pot as a hat. His advisor identified the image as the famous statue of Serapis, and Ptolemy felt it might unify the Egyptians and Greeks in Alexandria as well as incorporating the Babylonian religion. Despite three years' of resistance from the people of Sinope who did not want to part with it, the statue "magically" took itself by boat and installed itself in the new temple, called the Serapeum or Serapeion, in Alexandria. (Rosenbloom)
The earliest statues of Serapis from the Ptolemaic period did not have the hat. The hat appears in statues from the later Roman period. (Source: University College London) Eleni Vassilika writes: “The most popular cult image of Serapis shows him draped and regally enthroned, wearing his corn-basket kalathos-crown over thick wavy locks, with the triple-headed beast Cerberos seated at his side. The crown associated the god with the fruits of the earth, and the beast, possibly confused with the Egyptian jackal deity Anubis, was related to the god’s role as conveyor of the dead.” (Vassilika, p. 104) The kalathos is also known as a modius. “At the time of the Antonines,” Cumont wrote, referring to the Roman imperial rule from 138-180 CE, “there were forty-two Serapeums in Egypt.” (Cumont, pp. 74-75)
The name “Serapis” came from either Asar-Hapi (the Egyptian names for Osiris-Apis) or possibly the Chaldean deity Sar-Apsi. Chaldea was in southeastern Mesopotamia, northwest of the Persian Gulf.
Serapis, like Osiris, in Egypt was understood to be the brother/husband of Isis. He was believed to be the resurrection of the creator Ptah, who was ritually slaughtered, mummified, cremated, and then, in the form of the Apis bull, entombed. Apart from these broad associations, there are no surviving specific myths about Serapis.
Poems in honor of Serapis were written by the philosopher Demetrius of Phalerum who credited the god with curing his blindness. (Cumont, pp. 74-75) "Serapis’ blessing was sought for children and the sick, and he was regarded as a Saviour who spoke through oracles and in one’s dreams." (Vassilika, p. 104)
The Christian patriarch Theophilus, bishop of Alexandria, together with the Roman emperor Theodosius, axed the statue and torched the Serapeum in 391 CE, representing, in Rosenbloom's words, "the final destruction of paganism in Rome’s once tolerant empire." (Cumont, pp. 84-85; Rosenbloom) "An excellent evocation of this moment, when a syncretistic and sophisticated culture is nearly completely harassed out of existence by the rising single-minded zealotry, can be found in Georg Ebers’s 1885 novel Serapis [PDF], published in English translation [by Clara Bell, from the German] in New York the same year.” (Rosenbloom)
A British military ship named HMS Serapis launched in 1779 and was captured in 1781 by an American captain, John Paul Jones, whose own ship sank and who famously shouted, when things looked dimmest, “I have not yet begun to fight!” The ship was transferred to the French Navy in 1782. (Source: A page on modelships.co.uk, accessed 29 Dec 2003, that no longer exists)
Osborn Segerberg, Jr. The Immortality Factor. New York: E. P. Dutton and Co., Inc. 1974. Segerberg added: “The dynastic Ptolemies defied the ancient taboo and permitted dissection of human bodies.”
H. J. Rose. Religion in Greece and Rome. New York: Harper and Row, 1959. Originally published as Ancient Greek Religion (1946) and Ancient Roman Religion (1948), London: Hutchinson and Co., Limited.
Franz Cumont. The Oriental Religions in Roman Paganism. Authorized translation. Chicago: Open Court Publishing Company, 1911.
Eleni Vassilika. Greek and Roman Art
Eric Rosenbloom. "Serapis on the Liffey." 2003. Accessed Feb. 24, 2018.
"Memphis: Plaster head of Serapis," University College London, 2002, accessed 24 Feb 2018.
Stambaugh, John E. Sarapis under the early Ptolemies. Leiden, E. J. Brill, 1972.
Georg Ebers. Serapis. 1885.