Manetho was an Egyptian priest and annalist, was a native of Sebennytus in the Delta. The name which he bears has a good Egyptian appearance, and has been found on a contemporary papyrus probably referring to the man himself. The evidence of Plutarch and other indications connect him with the reigns of Ptolemy I. and II. His most important work was an Egyptian history in Greek, for which he translated the native records.
It is now only known by some fragments of narrative in Josephus's treatise Against Apina, and by tables of dynasties and kings with lengths of reigns, divided into three books, in the works of Christian chronologists. The earliest and best of the latter is Julius Africanus, besides whom Eusebius and some falsifying apologists offer the same materials; the chief text is that preserved in the Chronographia of Georgius Syncellus.
It is difficult to judge the value of the original from these extracts: it is clear from the different versions of the lists that they have been corrupted. Manetho’s work was probably based on native lists like that of the Turin Papyrus of Kings: even his division into dynasties may have been derived from such. The fragments of narrative give a very confused idea of Egyptian history in the time of the Hyksos and the XVIIIth Dynasty. The royal lists, too, are crowded with errors of detail, both in the names and order of the kings, and in the lengths attributed to the reigns.
The brief notes attached to some of the names may be derived from Manetho’s narrative, but they are chiefly references to kings mentioned by Herodotus or to marvels that were supposed to have occurred: they certainly possess little historical value. A puzzling annotation to the name of Bocchoris, "in whose time a lamb spake 990 years," has been well explained by Krall’s reading of a demotic story written in the twenty-third year of Augustus.
According to this a lamb prophesied that after Bocchoris’s reign Egypt should be in the hands of the oppressor 900 years; in Africanus’s day it was necessary to lengthen the period in order to keep up the spirits of the patriots after the stated term had expired. This is evidently not from the pure text of Manetho. Notwithstanding all their defects, the fragments of Manetho have provided the accepted scheme of Egyptian dynasties and have been of great service to scholars ever since the first months of Champollion’s decipherment.
See C. Muller, Fragmenta historicorum graecorum, ii. 511–616; A. Wiedemann, Aegyptische Geschichte (Gotha, 1884), pp. 121 et sqq.; J. Krall in Festgaben fur Budinger (Innsbruck, 1898); Grenfell and Hunt, El Hibeh Papyri, i. 223; also the section on chronology in Egypt, and generally books on Egyptian history and chronology.
1911 Encyclopaedia Britannica, Volume 17. pg. 567.