Atheists use the timeline in the MT in order to "prove" the bible wrong, saying it doesn't sync up with known history. This is an oddly light watch given the subject matter, and delves into the history of the pyramids and the Israelite sojourn in Egypt.
Essentially, ages in the genealogies were shortened, which throws off the timeline. If you compare with the greek septuagint there's a couple hundred years deleted from the MT. Sorry, but my explanation stops there, I'd essentially have to write a transcript. But he is a priest forever in the order of Melchizedek.