It was believed that the bulls were incarnations of the god Ptah, which would become immortal after death as Osiris-Apis, a name which evolved to Serapis (Σέραπις) in the Hellenistic period, and Userhapi (ⲟⲩⲥⲉⲣϩⲁⲡⲓ) in Coptic.

[2] Over a timespan of approximately 1400 years, from the New Kingdom of Egypt to the end of the Ptolemaic Period, at least sixty Apis are attested to have been interred at the Serapeum.

The quality of the inscriptions varies, the ones of Amasis II were beautifully executed, whereas those on an anonymous sarcophagus were only crudely scratched on the polished surface.

[6] The most ancient burials at the Serapeum, found in isolated tombs, date back to the reign of Amenhotep III of the Eighteenth Dynasty in the 14th century BC.

Khaemweset, working as an administrator during the reign of his father Ramesses II (1279–1213 BC) in the Nineteenth Dynasty, ordered a tunnel with side chambers – now known as the "Lesser Vaults" – to be excavated, for the burial of the Apis bulls.

From Amasis II to the end of the Ptolemaic dynasty, the sarcophagi for the Apis bulls were made of hard stone, weighing as much as 62 tonnes (68 short tons) each, including the lid.

[7] A long avenue, flanked by 370-380 sphinxes,[8] likely was built under Nectanebo I, (379/8–361/0 BC) the founder of the Thirtieth Dynasty (the last native one).

[14][15] The temple was discovered by Auguste Mariette,[16] who had gone to Egypt to collect Coptic-language manuscripts, but later grew interested in the remains of the Saqqara necropolis.

Many of them got destroyed when the Nile flooded the Museum of Egyptian Antiquities at Boulaq in 1878,[18][19] and the original diary of the excavations was borrowed by Eugène Grébaut but never returned.

[20] Gaston Maspero released one volume of Le Sérapeum de Memphis based on the surviving manuscripts in 1882, a year after Mariette's death.

[22] Prior to the installation of electric lamps, the tunnels were illuminated by a series of candles on wooden stands, and occasionally bright magnesium light was used.

[30] After the previous Apis had died the priests then sought out the young bull the soul of Osiris had migrated to, by identifying certain bodily marks.

Herodotus reported that it needed to be black, with a three-cornered white spot on its forehead, the likeness of an eagle on its back, double tail-hairs and a knot under its tongue.

[35] When an Apis died in the early days of the Serapeum, it was at least partially consumed and the remains conserved in a bituminous mass prior to interment.

[33] The bulls were buried in splendor, reportedly 100 talents (2.6 tonnes (5,700 lb) of silver) were spent by the caretakers for the obsequies at the time of Diodorus, in the first century BC.

[7] Mariette recognized traces of rollers on the floor of the galleries, and found two wooden horizontal winches, each operated with eight levers, in one of the niches.

[43] Heinrich Brugsch, visiting the Serapeum in 1853, noted that the "double-rails", on which the sarcophagi were rolled in, were still clearly preserved on the floor of the Ptolemaic service tunnel and the following passages.

For further protection, the ancient Egyptians cut recesses into the bedrock, about 1 metre (3.3 ft) deep, with the exact width and length of the sarcophagi.

[43] According to a stela found in the Serapeum, it took 28 working days to transport one of the sarcophagi and its lid into its burial chamber, in the 37th year of Ptolemy II, circa 247 BC.

Blocking the original entrance to the Greater Vaults is the "grey granite" sarcophagus dedicated by Cambyses II (c. 530 BC), first Persian ruler of Egypt.

[51] [Titulary of Cambyses II] He made as his monument to his father Apis-Osiris a large granite sarcophagus, dedicated by the king of Upper and Lower Egypt, Ms-tjw-Re, son of Re, Cambyses, endowed with all health and prosperity in perpetuity, all health, all joy, appearing as the king of Upper and Lower Egypt for eternity.

[52] Year 2, month Athyr, under the Majesty of King Khabash, the friend of Apis-Osiris, of Horus "of Kakem" (a name for the locality of the Apis tombs) Only one of the sarcophagi of the Ptolematic section is inscribed.

In the bedrock beneath, a sloping passage led to a rectangular chamber which housed coffins with the remains of the bull, canopic jars and other burial items.

Isolated Tombs were constructed in the 18th and 19th dynasty of Egypt, during a timespan of about 160 years (c. 1390 – c. 1250 BC), between the reigns of Amenhotep III and Ramesses II.

Working as an administrator during the reign of his father, Khaemweset, a son of Ramesses II (1279–1213 BC) of the Nineteenth Dynasty, ordered that a tunnel be excavated at the site, and a catacomb of galleries – now known as the "Lesser Vaults" – be designed with side chambers to contain the sarcophagi for the mummified remains of the bulls.

[38] A stela, now located in the Louvre, attests the renovation of the Serapeum and its expansion:[64] [Titulary of Psamtik I] In the year 52, under the reign of this god, information was brought to his Majesty: 'The temple of thy father Osiris-Apis, with what is therein, is in no choice condition.

His Majesty caused all that is due to a god to be performed for him (the deceased bull) on the day of his burial....[38] A sarcophagus dedicated by Cambyses II obstructs the original entrance way to the Greater Vaults.

30 years later, for the burial of the third Apis, a considerably larger approach into the Greater Vaults was cut by extending the main ramp westwards beyond the old entrance stairway to a door in the bedrock, where a corridor was excavated to the south until it joined the Psamtik I gallery.

The votive stelae, previously fixed to the outside of the masonry that closed each burial chamber, were now put up collectively on the walls of the entrance and the new tunnel leading to the Ptolemaic section.

'This is what was done for him by Aahmes-se-Nit, who bestows pure life forever' A stela, dedicated to the first Apis that died in year 4 of Darius, states:[40] Year 4, third month of the Season of the Harvest, day 13, under the majesty of the king of Upper and Lower Egypt Darius, endowed with life [as] Ra [forever...], this god was led in [peace] towards the beautiful west and was left to rest in the necropolis, in his place which is the place which his majesty had made for him - we had never [done the same thing before - after having done all the ceremonies] in the embalming room.