I have a DNA match to my 8th great grandmother, presumably sharing about 9 cMs. She was married 3 times and had children with each husband, and my match has tons of surnames in her family tree that are descended from this matriarch and her husbands. The ancestor's line and progeny is extremely well-researched because she was part of an early 18th Century German colony in Virginia which is currently a historical site; although to date, there is not an autosomal DNA group, but there is a yDNA group at FTDNA. The first two or three immigrant generations tended to married other Germans in their colony, and although my direct line from her does not show evidence of cousin marriages (I am from her first husband, who had only one child with her before he died), she had seven children in total, and their offspring married cousins. It is said she is the "Mother of Germanna", so I think it's quite possible that this match is authentic.

Admittedly, I would still need a couple of more matches on this segment to verify that I am still carrying a measurable piece of Anna Barbara Schone's DNA. However, before Ancestry changed it's algorithm, I had probably 10 distant cousin hints pointing to Anna Barbara as being our common ancestor (my mother had more than that). Also, I have 6 DNA Circles pointing to 5th great grandparents.