Types of historic record change as you go back in time. The first hundred years back or so, would be state BDM records. The next several hundred years, depending on where you are, would be church records. The records I have older than that, are heraldry records, which don't have a great deal of dates. Older than that, tends to be other historic documents. When you get back to Bible era, the Bible itself is considered by historians to be the best attested document available, and they could only wish they had so many documents to prove other historic figures. Of course, the historic record all the way through, is backed up by archaeology. From finding grave details, to finding coins and pottery. Standards don't necessarily deminish, as there is a massive amount of work available on textual criticism. Of course, most of it aimed at the Bible, because it seems to always be presumed wrong, but other sources seem to be assumed right.
I'm not sure why the question was drawn to your attention after I put an answer up. (Not that I'm worried, or critical of that) I was aware that it was four years old, when I answered. My wife has ordered for me 'After The Flood', which details genealogies that proceed from the Table of Nations in Genesis 10, so I thought I'd just comment my wish again, that Wikitree would allow some sort of way to start producing BC profiles. Even if Wikitree could produce a side system to handle it. Anyway. There was no point starting a new question over it, because I'm already aware of the answer.