He was probably a priest of the sun god Ra at Heliopolis (according to Syncellus, he was the chief priest), and was also considered an authority on the cult of Sarapis (a derivation of Osiris-Apis). Sarapis itself was a Greco-Macedonian annexation of the Egyptian cult, probably started after Alexander the Great's establishment of Alexandria in Egypt. A statue of the god was imported between 286 and 278 BCE by Ptolemy (either Soter or Philadelphos), where Timotheus of Athens (an authority on Demeter at Eleusis) and Manetho oversaw the project.
Some have suggested that Aegyptiaca was written as a competing account to Herodotus' Histories of Herodotus, to provide a national history for Egypt that did not exist before. From this perspective, Against Herodotus may have been an abridged version or just a part of Aegyptiaca that circulated independently. Unfortunately, neither survives in its original form today.
The earliest surviving attestation to Manetho is that of Josephus' Contra Apionem, "Against Apion". Even here, it is clear that Josephus did not have the originals, and constructed a polemic against Manetho without them. Avaris and Osarsephos are both mentioned twice (1.78, 86-87; 238, 250). Apion 1.95-97 is merely a list of kings with no narratives until 1.98, while running across two of Manetho's dynasties without mention (Dynasties XVIII and XIX). Many scholars have attempted to recreate which portions were written by the anti-Jewish, pro-Jewish, anti-Egyptian, pro-Egyptian, anti-Greek and pro-Greek writers, but the conclusions have been disputed.
Contemporaneously or perhaps after Josephus wrote, an Epitome, or summary, of Manetho's work must have appeared. This would have involved preserving the outlines of his dynasties and a few details deemed significant. For the first ruler of the first Dynasty, Menes, we learn that "He was snatched and killed by a hippopotamus". The extent to which the epitome preserved Manetho's original writing is unclear, so caution must be exercised. Nevertheless, the epitome was preserved by Sextus Julius Africanus and Eusebius, bishop of Caesarea (Chronicon). Because Africanus predates Eusebius, his version is usually considered more reliable, but there is no assurance that this is the case. Eusebius in turn was preserved by Jerome in his Latin translation, an Armenian translation, and by Syncellus. Syncellus recognized the similarities between Eusebius and Africanus, so he placed them side by side in his work, Ecloga Chronographica.
These last four copies are what remains of the epitome of Manetho. Other significant fragments include Malalas' Chronographia and Excerpta Latina Barbari, "Excerpts in Bad Latin". The route of transmission for the bulk of Manetho's work is given in the table below (adapted from Verbrugghe and Wickersham 2000:118).
The provenance of the Old Kingdom Annals is unknown, surviving as the Palermo Stone. The differences between the Annals and Manetho are vast. The Annals only reach to the fifth dynasty, but its pre-dynastic rulers are listed as the kings of Lower Egypt and kings of Upper Egypt. By contrast, Manetho lists several Greek and Egyptian gods beginning with Hephaistos and Helios. Secondly, the Annals give annual reports of the activities of the kings, while there is little probability that Manetho would have been able to go into such detail.
The New Kingdom lists are each selective in their listings: that of Seti I, for instance, lists seventy-six kings from Dynasties I to XIX omitting the Hyksos rulers and those associated with the heretic Akhenaten. The Saqqara list, contemporaneous with Ramesses II, has fifty-eight names, with similar omissions. If Manetho used these lists at all, he would have been unable to get all of his information from them alone, due to the selective nature of their records. Verbrugghe and Wickersham argue:
Furthermore, the purpose of these lists was to cover the walls of a sacred room in which the reigning Pharaoh (or other worshiper, as in the case of Tenry and his Saqqara list) made offerings or prayers to his or her predecessors, imagined as ancestors. Each royal house had a particular traditional list of these "ancestors," different from that of the other houses. The purpose of these lists is not historical but religious. It is not that they are trying and failing to give a complete list. They are not trying at all. Seti and Ramesses did not wish to make offerings to Akhenaten, Tutankhamen, or Hatshepsut, and that is why they are omitted, not because their existence was unknown or deliberately ignored in a broader historical sense. For this reason, the Pharaonic king-lists were generally wrong for Manetho's purposes, and we should commend Manetho for not basing his account on them (2000:105).
These large stelae stand in contrast to the Turin Royal Canon (like Saqqara, contemporaneous with Ramesses II), written in hieratic script. Like Manetho, it begins with the gods, and like Manetho, appears to be an epitome very similar in spirit and style to Manetho. Interestingly, the opposite side of the papyrus includes government records. Verbrugghe and Wickersham suggest that a comprehensive list like this would be necessary for a government office "to date contracts, leases, debts, titles, and other instruments (2000:106)" and so could not have been selective the way the king-lists in temples were. Despite numerous differences between the Turin Canon and Manetho, the format must have been available to him. As a priest (or chief priest), he would have had access to practically all written materials in the temple.
While the precise origins for Manetho's kinglist are unknown, it was certainly a Northern Lower Egyptian one. This can be deduced most noticeably from his selection of the kings for the Third Intermediate Period. Manetho consistently includes the Tanite Dynasty 21 and Dynasty 22 line in his Epitome such as Psusennes I, Amenemope and even such short-lived rulers here like Amenemnisu (5 years) and Osochor (6 years). In contrast, he ignores the existence of Theban kings such as Osorkon III, Takelot III, Harsiese A and Pinedjem I and rulers from Middle Egypt like Peftjaubast of Herakleopolis. This implies that Manetho derived the primary sources for his Epitome from a local city's temple library in the Delta Region which was under the control of the Tanite based Dynasty 21 and Dynasty 22 kings. The Middle and Upper Egyptian Pharaohs had no impact upon this specific region of the Delta; hence their exclusion from Manetho's kinglist.
As such, Manetho did not pick consistently from the five different types of names, but in some cases, a straightforward transcription is possible. Egyptian Men or Meni (Son of Ra and king-list names) becomes Menes (officially, this is Pharaoh I.1 Aha—"I" represents Dynasty I, and "1" means the first king of that dynasty), while Menkauhor/Menkahor (Throne and king-list names, the Horus names is Menkhau and the Son of Ra name is "Kaiu Horkaiu[...]") is transcribed as Menkheres (V.7 Menkauhor). Others involve a slight shortening, such as A'akheperen-Re' (Throne and king-list names) becoming Khebron (XVIII.4 Thutmose II). A few more have consonants switched for unknown reasons, as in Tausret becoming Thouoris (XIX.6 Twosre/Tausret). One puzzle is in the conflicting names of some early dynastic rulers—though they did not have all five titles, they still had multiple names. I.3/4 Djer, whose Son of Ra name is Itti is seen as the basis for Manetho's I.2 Athothis. I.4 Oenephes then is a puzzle unless it is compared with Djer's Gold Horus name, Ennebu. It may be that Manetho duplicated the name or he had a source for a name unknown to us. Finally, there are some names where the connection is a complete mystery to us. V.6 Rhathoures/Niuserre's full name was Set-ib-tawi Set-ib-Nebty Netjeri-bik-nebu Ni-user-Re' Ini Ni-user-Re', but Manetho writes it as Rhathoures. It may be that some pharaohs were known by names other than even just the five official ones.
Thus, how Manetho transcribed these names varies, and as such we cannot reconstruct the original Egyptian forms of the names. However, because of the simplicity with which Manetho transcribed long names (see above), they were preferred until original king-lists began to be uncovered, translated, and corroborated in ancient Egyptian sites. Manetho's division of dynasties, however, is still used as a basis for all Egyptian discussions.
Volume 2 covers Dynasties XII - XIX, which includes the end of the Middle Kingdom and the Second Intermediate Period (XV-XVII—the Hyksos invasion), and then their expulsion and the establishment of the New Kingdom (XVIII onward). The Second Intermediate Period was of particular interest to Josephus, where he equated the Hyksos or "shepherd-kings" as the ancient Israelites who eventually made their way out of Egypt (Apion 1.82-92). He even includes a brief etymological discussion of the term "Hyksos".
Volume 3 continues with Dynasty XX and brings it to a conclusion in Dynasty XXX (or XXXI, see below). The Saite Renaissance comes in Dynasty XXVI, while XXVII involves the Achaemenid interruption to Egyptian rule. Three more local dynasties are mentioned, though they must have overlapped with Persian rule. XXXI consisted of three Persian rulers, and some have suggested that this was added by a continuator. Both Moses of Chorene and Jerome end at Nectanebo ("last king of the Egyptians" and "destruction of the Egyptian monarchy" respectively), but XXXI fits within Manetho's schemata of demonstrating power through the dynasteia well. The Thirty-second dynasty would have been the Ptolemies.
Syncellus goes so far as to insinuate that the two copied each other:
If one carefully examines the underlying chronological lists of events, one will have full confidence that the design of both is false, as both Berossos and Manetho, as I have said before, want to glorify each his own nation, Berossos the Chaldean, Manetho the Egyptian. One can only stand in amazement that they were not ashamed to place the beginning of their incredible story in each in one and the same year. (Ecloga Chronographica, 30)
While this does seem an incredible coincidence, the reliability of the report is unclear. The reasoning for assuming they started their histories in the same year involved some considerable contortions. Berossos dated the period before the Flood to 120 saroi (3,600 year periods), giving an estimate of 432,000 years before the flood. This was unacceptable to later Christian commentators, so it was assumed he meant solar days. 432,000 divided by 365 days gives a rough figure of 1,183½ years before the Flood. For Manetho, even more numeric contortions ensued. With no flood mentioned, they assumed that Manetho's first era describing the gods represented the ante-diluvian age. Secondly, they took the spurious Book of Sothis for a chronological count. Six dynasties of gods totalled 11,985 years, while the nine dynasties with demigods came to 858 years. Again, this was too long for the Biblical account, so two different units of conversion were used. The 11,985 years were considered to be months of 29½ days each (a conversion used in antiquity, for example by Diodorus Siculus), which comes out to 969 years. The latter period, however, was divided into "seasons", or quarters of a year, and reduces to 214½ years (another conversion attested to by Diodorus). The sum of these comes out to 1,183½ years, equal to that of Berossos. Syncellus rejected both Manetho's and Berossos' incredible time-spans, as well as the efforts of other commentators to harmonise their numbers with Scripture. Ironically as we see, he also blamed them for the synchronicity concocted by later writers.
Syncellus similarly recognised its importance when recording Eusebius and Africanus, and even provided a separate witness from the Book of Sothis. Unfortunately, this material is likely to have been a forgery or hoax of unknown date. Every king in Sothis after Menes is irreconcilable with the versions of Africanus and Eusebius. Manetho should not be judged on the factuality of his account, but on the approach he took to recording history, and in this, he was as successful as Herodotus and Hesiod.
Finally, in modern times, the impact is still visible in the way Egyptologists divide the dynasties of the pharaohs. The French explorer and Egyptologist, Jean-François Champollion, reportedly carried a copy of Manetho's lists in one hand as he attempted to decipher the hieroglyphics he encountered (though it probably gave him more frustration than joy, considering the way Manetho transcribed the names). Most modern scholarship that mentions the names of the pharaohs will render both the modern transcription and Manetho's version, and Manetho's names are even preferred to more authentic ones in some cases. Today, his division of dynasties is universally used, and this has permeated into the study of nearly all royal genealogies through the understanding of succession in terms of dynasties or houses.