We could certainly do with an in-depth response on this with some high-quality documentation, but while we're waiting, there have been some briefer answers in the past that have addressed the thrust of the question:

• responses by /u/Alkibiades415 and /u/PreviousDrawer: https://old.reddit.com/r/AskHistorians/comments/dduble/can_someone_give_a_concise_summary_of_what_a/
• response by /u/BetaKeyTakeaway: https://old.reddit.com/r/AskHistorians/comments/29wfcq/egyptologists_how_was_the_age_of_the_great_sphinx/
• responses by /u/Nebkheperure and others: https://old.reddit.com/r/AskHistorians/comments/179r5h/did_the_egyptians_really_build_the_pyramids_or/ (ignore the nutty exchange in the replies about Atlantis)

This has come up before on the sub and while more can always be said, here's a collection of threads by /u/Bentresh about the subject while you're waiting:

https://www.reddit.com/r/AskHistorians/comments/f3mkai/for_those_that_are_familiar_with_him_how_do_you