Besides DNA testing I do not believe that it can be said with any certainty that one is related to famous figures of the past going back that far in time. I see trees like this all of the time on Ancestry and other genealogical websites. For example, I've seen family trees saying that one of my 2x great grandfathers who fought in the Civil War is a direct descendant of Robert Bruce of Scotland through a love affair he had outside of marriage. While there is a slim chance this could be true, tracing family lines back in time without evidence except family lore and legends leads to many incorrect assumptions and misleading family histories. I've even seen family trees tracing one of my family lines back to Charlemagne which I find to be dubious at best.
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