During colonization of the conquered Egypt, Greek and Roman authors had much to say about Apis, the markings by which the black calf was recognized, the manner of his conception by a ray from heaven, his house at Memphis (with a court for his deportment), the mode of prognostication from his actions, his death, the mourning at his death, his costly burial, and the rejoicings throughout the country when a new Apis was found.

Auguste Mariette's excavation of the Serapeum of Saqqara revealed the tombs of more than sixty animals, ranging from the time of Amenhotep III to the end of the Ptolemaic dynasty.

Creating parallels to their own religious beliefs, ancient Greek writers identified Apis as an incarnation of Osiris, ignoring the connection with Ptah.

Apis came to being considered a manifestation of the king, as bulls were symbols of strength and fertility, qualities that are closely linked with kingship.

As early as the time of the Narmer Palette, the king is depicted with a bovine tail on one side, and a bull is seen knocking down the walls of a city on the other.

In the region where Ptah was worshiped, cattle exhibited white patterning on their mainly black bodies, and so a belief grew up that the Apis calf had to have a certain set of markings suitable to its role.

The earliest known burial in Saqqara was performed in the reign of Amenhotep III by his son Thutmose; afterward, seven more bulls were buried nearby.

[6] The careful documentation of the ages of the animals in the later instances, with the regnal dates for their birth, enthronement, and death have thrown much light on the chronology from the Twenty-second Dynasty onward.

As a form of Osiris, ruler of the underworld, it was believed that to be under the protection of Apis would give the person control over the four winds in the afterlife.

According to Arrian, Apis was one of the Egyptian deities Alexander the Great propitiated by offering a sacrifice during his seizure of Ancient Egypt from the Persians.

[7] After Alexander's death, his general Ptolemy I Soter made efforts to integrate Egyptian religion with that of the new Hellenic rulers.

The significance of this Serapsi in the Hellenic psyche, however, due to its involvement in Alexander's death, also may have contributed to the choice of Osiris-Apis as the chief Ptolemaic deity during their occupation of Ancient Egypt.

Also, according to Tacitus, Serapis (i.e. Apis explicitly identified as Osiris in full) had been the tutelary deity of the village of Rhacotis, before it suddenly expanded into the great capital of "Alexandria".

With his (i.e., Osiris') wife, Isis, and their son (at this point in history) Horus (in the form of Harpocrates), Serapis won an important place in the Greek world, reaching Ancient Rome, with Anubis being identified as Cerberus.