Because of the aforementioned differences in spelling, he didn't recognize Khufu on Manetho's king list (as transcribed by Africanus and Eusebius),[43] hence he relied on Herodotus' incorrect account. Summating the duration of lines of succession, Greaves concluded the year 1266 BC to be the beginning of Khufu's reign.[23]
Two centuries later, some of the gaps and uncertainties in Manetho's chronology had been cleared by discoveries such as the King Lists of Turin, Abydos, and Karnak. The names of Khufu found within the Great Pyramid's Relieving Chambers in 1837 helped to make clear that Cheops and Souphis are, in fact, one and the same. Thus the Great Pyramid was recognized to have been built in the 4th dynasty.[25] The dating among Egyptologists still varied by multiple centuries (around 4000–2000 BC), depending on methodology, preconceived religious notions (such as the biblical deluge) and which source they thought was more credible.
Estimates significantly narrowed in the 20th century, most being within 250 years of each other, around the middle of the third millennium BC. The newly developed radiocarbon dating method confirmed that the historic chronology was approximately correct. 