The dominant triad of Egyptian gods, during the Roman period, was composed of Sarapis, Isis, and Harpokrates. Isis, the great mother goddess, originated in Egyptian prehistory, and was worshipped continuously for over 4000 years. At one time, the Isis worshippers were gaining converts in the Roman empire at a faster pace than the Christians. Horus, usually identified as the son of Isis, enjoyed much the same popularity. Also venerated by the Egyptians for over 4000 years Horus had many attributes and characteristics that varied from cult to cult, and period to period. During the Roman period, Horus was worshipped in Alexandria under the Graeco-Egyptian form of Harpokrates.

Sarapis the all powerful male god, was an invention of the early Ptolemies, who tried to combine elements of divinity that would appeal to both their Greek and Egyptian subjects. The venture was quite successful. In Sarapis was found attributes of Osiris (ancient Egyptian god of the dead and of eternal life, and mate of Isis), of Apis (sacred bull, reincarnating the spirit of Ptah), and of Horus. The very name "Sarapis" is a compound of the names of these older gods.

Sarapis became so important in the Roman world that he not only appeared frequently on the regular Roman coinage, but even so remote an usurper as Postumus in Gaul used his standing figure as a reverse type on both gold and silver coins. So omnipotent was Sarapis sometimes considered, that on Alexandrian coins he was often represented as having assimilated attributes of other major gods, in a first groping step toward monotheism.

On Plate I will be found Sarapis Pantheistic, as represented on both a tetradrachm of Marcus Aurelius and a drachma of Antoninus Pius. On the tetradrachm he is shown with attributes of Zeus, Ammon Nilus, Herakles, and Asklepios. The drachma depicts him with attributes of Ammon, Helios, Poseidon and Asklepios. On the same plate, a tetradrachm shows a conventional bust of Sarapis, while an unpublished drachma shows a bust of Sarapis-Ammon. The latter type is quite rare. Plate I is completed by two drachmas which show the bust of Sarapis above an eagle and above a ram.

On Plate II will be found two unpublished drachmas, one of which represents Sarapis seated with Kerberos (Severus Alexander), and the other depicting Sarapis, as a fountain god, seated by a lebes (Lucius Verus). Two tetradrachms of Hadrian show Sarapis standing accompanied by Kerberos, and Sarapis-Nilus standing by an altar. To complete Plate II, we find the head of Sarapis, with a serpent's body, on a drachma of Pius, and Sarapis and Isis busts jugate, on a tetradrachm of Philip II.

The bust of Isis on a tetradrachm of Julia Mamaea, the standing figure of Isis-Tyche on a tetradrachm of Pius, and Isis nursing Harpokrates, on a diobol of Hadrian, form the top line of Plate III. The latter coin is unpublished. These are followed by Isis seated (half-drachma of Hadrian), and Isis Pharia, patron goddess of sailors and waylarers, facing the Pharos lighthouse (drachma of Hadrain). The table is completed by two drachmas; on that of Trajan, Isis-Hathor stands between Horus (in hawk form) and an altar; while on that of Pius, Isis Euploia stands between Nilus and Euthenia, with prows of ships in the background.

Plate IV depicts Harpokrates (or Horus) in a variety of forms. On the top line will be found the bust of Harpokrates on an obol of Hadrian, and the bust of Harpokrates of Herakleopolis on an extremely rare diobol of Commodus. We next see Horus, in hawk form, wearing a crown (obol of Nero), and Harpokrates standing (drachma of Hadrian). Two drachmas of Trajan portray Harpokrates standing between sphinxes on altars (unpublished), and Harpokrates of Canopus, with crocodile body, standing on an altar.

Nilus and Euthenia seem to have been next in importance to the great triad, so far as Alexandria and the coinage are concerned. Nilus was the god of the river Nile, upon which the life of Egypt depended. Although in Pharaonic times, under the name "Hapi," he had been regarded as a minor divinity, he rose to great prominence at Alexandria during the Roman era. The mint artists seemed to be particularly free in their treatment of this god, and took an apparent delight in developing an almost endless series of types and varieties to represent him. He was frequently assimilated to Osiris, and thus to Sarapis.

Euthenia was a very late addition to the Egyptian pantheon. Originally the personification of "abundance" or "plenty," and represented on the regular coins of Rome as Abundantia, she became the consort of Nilus, during Ptolemaic times, and acquired the status of an important goddess. She was often assimilated to Isis.

Plate V presents some of the more interesting types of Nilus. His bust, with a small genius (probably Ploutos) in front, and a lotus behind, is shown as it occurs on an extremely rare tetradrachm of Domitian. A second bust, with a cornucopia by the shoulder, is from a common tetradrachm of Hadrian. The center row gives two illustrations of Nilus reclining. On a drachma of Antoninus Pius, he holds a cornucopia, from which a genius emerges holding a wreath. A crocodile crawls upward from the exergue. The Greek letters "IS" (which represent the figure 16) above, refer to a 16 cubit Nile level, which would guarantee a year of good crops and prosperity. The other type, from a tetradrachm of Severus Alexander, again represents Nilus reclining, holding a cornucopia. This time, the genius reaches toward Nilus, whose head is turned, while three little genii march playfully up his leg. On the bottom row, a tetradrachm of Hadrian portrays Nilus seated over a crocodile, and a very rare drachma of Antoninus Pius presents a rather ludicrous picture of Nilus riding on a hippopotamus.

On the top row of Plate VI will be seen two representations of Nilus seated by a standing figure of Euthenia. The first is from an unpublished drachma of Antoninus Pius, and the second from an unpublished tetradrachm of Philip I. Below these we find the jugate busts of Nilus and Euthenia, from a tetradrachm of Elagabalus, and the bust of Euthenia alone, from a diobol of Agrippina. The plate is completed by two half-drachma reverses. On that of Hadrian, Euthenia is depicted reclining, holding corn ears. On that of Faustina Jr. Euthenia is shown standing, hoiding corn ears and a short scepter. Only one other specimen of this last coin is known.

Hermanubis was another god of rather complicated origins. One of the most ancient of all Egyptian gods was the jackal-headed Anubis (Anpu), who among other things served as guide to the souls of the dead. In time, a compound form of Anubis and Horus arose, designated as Harm-Anubis. It was an easy step to identify this form with the Greek god Hermes, and to thus develop the final name "Hermanubis." Although the coin types always depict Hermanubis with a human head, his identification with Anubis is usually evidenced by an attendant jackal.

Ptah was the ancient chief god of Memphis, capital of Egypt during the earlier dynasties. Among his many attributes, he was particularly noted as patron of artisans and skilled workmen. He was prominent throughout Egypt from an early period. His single appearance on coins was during Hadrian's 20th Alexandrian year, at which time he was represented in two different aspects on a rather extensive issue of tetradrachms. One type represented him as the purely Egyptian Ptah-Sokar-Osiris, while the other identified him with a Greek divinity as Ptah-Hephaistos. This single appearance was hardly due to chance. As patron of artisans, he might well have been placed on the coinage as a substitute for Moneta, or more likely, in recognition of the skilled efforts which had implemented the great plan of building and construction inaugurated by Hadrian five years previously.

Ammon's classification has often been considered controversial, but it seems proper to include him in the series of Egyptian gods. As represented on the Alexandrian coinage, he combined elements of the ancient Egyptian Amen-Re (dominant divinity during the ascendancy of the Theban dynasties), Ammon of the Lybian Siwa Oasis, and the Thracian Ammon introduced by the Ptolemies. He is always depicted with a ram's horn at his temple, as was Amen-Re during Pharaonic times. He was closely identified with the Greek god Zeus.

Plate VII presents two coin types of Hermanubis, two types of Ptah, and two varieties of Ammon. The bust of Hermanubis is from a tetradrachm of Elagabalus, while the standing figure is from one of Philip II. The types of Ptah-Sokar-Osiris and Ptah-Hephaistos are both from tetradrachms of Hadrian. One variety of Ammon head is from an extremely rare diobol of Antoninus Pius, while the other is from an unpublished drachma of Philip II. Among the few coin types of Alexandria that represented ancient Egyptian religious motifs unchanged by Greek influences, were those of the Canopi. The Canopus was a jar or vase in which the viscera of the deceased were placed during the embalming process. These were interred beside the mummy. The canopic jar itself was finished and decorated to bear a general resemblance to a mummy. Originally, the four canopic vases of a burial bore the heads of Osiris's four children, of which one was human and three were animal. The Canopi depicted on the coin types, however, always bore the head of Osiris or the head of Isis. Frequently a coin type included pairs of Canopi.

Plate VIII presents a variety of Canopic types. The two in the upper part depict representations of the Canopus of Osiris as shown on a tetradrachm of Antoninus Pius, and as presented on a tetradrachm of Gallienus. The latter is quite rare. Below these will be found a Canopus of Osiris from a drachma of Hadrian, and a Canopus of Isis from a tetradrachm of the same emperor. The plate is completed by two drachmas showing pairs of Canopi.