The further back in time you go, the more difficult it is to piece together the information from the official documents of the time and make sure that the few items from church records, wills, land records and court records (as mentioned by Kathie) really belong to one and the same person. It's all too easy to construct a profile from a birth record belonging to one individual and a death record for another. (I have even fallen into that trap a few times myself).
At the same time, these our oldest ancestors have been researched for a long time - so with time it can get quite complicated to separate the credible genealogies from those with a lot of wishful thinking.
I see that you are a descendant of
https://www.wikitree.com/wiki/Fleming-1141 Thomas Alexander Fleming. This is not my part of the world, but I find that profile as confusing as you do. There seems to be an old controversy and as the profile is organized at the moment it does not explain very well what we are to believe and what not.
