Looking back even further

[MasterMel]

How would I discover if I'm related to someone substantial from the middles Ages and onward?

[jova99]

500 years ago

10 generations back you would have 1,024 GGGGGGGGG Grandparents...and on average you would get 0.097% of your DNA from each one.

20 generations back would be around the year 1500 and you would have over 500,000 Great Grandmothers and 500,000 Great Grandfathers

21 generations back you would have over 2 million 19th Great Grandparents.

22 generations back you have 4 million 20th Great Grandparents

23 generations back you have 8 million great grandparents...which would be 12% of the population of Europe in the year 1425.

24 generations back you have 16 million Great grandparents..24% of the European population.
So the odds are high you are related to Charlemagne, as is every European alive today.

[MoberlyDrake]

Best way would be very careful and thorough genealogical research and that might take you a lifetime. Since you don't receive DNA from all of your ancestors, chances are, that even if a particular person who lived in the Middle ages was your ancestor, you don't have any DNA from that person or, if you do have a small segment, it would be next to impossible to prove it came from that person.

Now if you believe the person was a direct paternal ancestor (no breaks in passing the Y-DNA down in all those generations) you could possibly determine whether you were in the same haplogroup anyway, but if it is a common haplogroup, it wouldn't mean much. The same would apply to a direct female ancestor with no breaks in the transmission of the mitochondrial DNA. Neither would prove you are a descendant, but they might tell you you can't be. But the chances of finding enough other descendants who have already tested might be slim.

[John McCoy]

Ultimately, the issue for such remote ancestors has to do with finding and evaluating primary sources -- not a simple matter by any means! Even when the "original" texts can be read with certainty, they may not be what they purport to be, they may be incorrect or even purposely misleading, and they may not have been created when or by whom they claim. Genetic evidence may have a bearing on proving medieval ancestry, but only when considered with other types of evidence.