I will be going through all of the DNA matches on Ancestry where they share a common ancestor. In the end it comes down to their research being correct as well as mine. There are several matches back to our common ancestors in that line, and provided the person is correct in that someone is really their ancestor and hasn't just copied from family tree, then I can safely say that John Andrew was the biological son of Julia Knox. There would be no other way of being a match otherwise. The paper trail has to be correct as we don't have DNA samples from our ancestors.
Yes, I agree with your 2nd sentence.
You could have a 100% dna match, but if either party has gone wrong just once, in their paper trail research, DNA matches prove nothing.
Somewhere I posted a link to the Leicester University research of the King found buried under the Leicester Car Park.
I believe considerable time was spent looking for sources, finding documents and then visiting archives to see them.
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A line from my Family Tree (who married an Arundel), it was claimed their family name was related to the Earl and when she married they even named a son Bernard, but with the middle name Pearson (it makes no sense).
However, the family folklore may have been just to cover up for a 19th Century illegitimate Birth of theirs (recorded on the baptism register as illegitimate), but the Mother did appear to marry the Father according to the Census, but some folklore may be true.
Mark