Manetho wrote a book, the Aegyptiaca, in the third century BCE, which outlined the history of Egypt and served as the basis for the chronology of Egypt down to the modern era. As such, Greek historians preserved its outlines in their own works in order to provide support for their chronologies, sometimes making changes and emendations in order to fit it into Christian schema. Most of these fragments appear in the works of Eusebius in the fourth century and George Syncellus around 800 CE.
Here’s how I came across the conspiracy (of sorts): The text I was using for Manetho came from E. Richmond Hodges’s 1876 edition of Cory’s Ancient Fragments, but the editor made several inexplicable errors, most of which seem to reflect his religious background (he was a priest in the Anglican Church), such as when he erroneously retranslated a passage to make Khufu into Enoch, where the original lacks such a claim. Anyway, to fix this, I corrected the text against Cory’s 1832 translation, which, while less readable, tends toward more accurate.
In so doing, I noticed that Hodges left out a lot of the material Cory had assembled on some of the other fragments of Manetho, which, to be frank, I never spent a lot of time studying. Cory attributed one interesting epitome of Manetho to the ancient writer Castor of Rhodes, but seemed to be entirely false. So I got out the Loeb edition of Manetho, in which the same passage is ascribed to the Excerpta Latini Barbari, known in English as the Excerpts in Bad Latin. It appears on folio 38a, for what it’s worth. The text remained untranslated into English until 2012.
I’d never heard of this text, but it turns out to be part of a Merovingian conspiracy. The surviving text, written in poor Latin, is a Merovingian translation from around 750 CE of a Greek-language world chronicle, probably first composed within a decade of 500 CE. The translation, which is all that remains of the now-lost Greek text, is replete with mistakes large and small. The translator was particularly ignorant of Greek names and tended to render them phonetically. Thus, Hephaestus, for example, is translated as Ifestus instead of Vulcan, and other Greek terms were mangled practically beyond recognition.
Most importantly, the text inserts into the Greek a fake genealogy of the Merovingians linking them to the Trojans, similar to the genealogy appearing in the near-contemporary Liber Historiae Francorum. That book, in turn, rewrote Gregory of Tours’s history to shoehorn a Merovingian-Trojan connection. The long and short of it is that the forebear of the Franks, Francus, ended up inserted into the list of kings of Alba Longa as the fifth descendant of Aeneas, the Trojan hero who gave rise to the race of Rome. Thus the Merovingians, descendants of Francus, were “really” kin to the Romans and heirs to the Empire. This story, unknown to Gregory, must therefore have emerged in the seventh century. (Update: As the comments below indicate, the claim appears in the Chronicle of Fredegar around 650 CE.)
This real-life conspiracy raises an important problem for the Holy Bloodline theorizers who attribute a great deal of historical revisionism to the Merovingians. If, after all, their claim to power was a connection to Christ, why did they bother falsifying pagan histories? One might argue it was entirely to keep the Holy Bloodline secret, but this claim is undercut by Holy Bloodline authors’ ignorance of real-life historical revisionism. For example, the authors of The Holy Blood and the Holy Grail know vaguely that such claims occurred but are ignorant of the primary sources or of the historical revisionism that occurred:
We could find little verifiable information about the true origins of the Merovingians. They themselves claimed descent from Noah, whom they regarded, even more than Moses, as the source of all Biblical wisdom an interesting position, which surfaced again a thousand years later in European Freemasonry. The Merovingians also claimed direct descent from ancient Troy which, whether true or not, would serve to explain the occurrence in France of Trojan names like Troyes and Paris. […] At some unspecified date towards the advent of the Christian era they supposedly migrated up the Danube, then up the Rhine, and established themselves in what is now western Germany. Whether the Merovingians derived ultimately from Troy or from Arcadia would now seem to be academic, and there is not necessarily a conflict between the two claims.
The effort to connect dynasties back to the Trojan and the Romans was hardly confined to the Merovingians. The Habsburgs, for example, called themselves descendants of Aeneas, and Snorri Sturluson traced the line of Norse kings back to the gods, who were human kings and refugees from Troy.