"Millions of people have provable descents from medieval monarchs," said Mark Humphrys, a genealogy enthusiast and professor of computer science at Dublin City University in Ireland. "The number of people with unprovable descents must be massive."By the same token, for every king in a person's family tree there are thousands and thousands of people whose births, lives and deaths went completely unrecorded by history. We'll never know about them, because until recently vital records were rare for all but the noble classes.