But what does that really mean? James Tanner commented in a recent blog post (Genealogy is not a competitive sport) about family trees that contain thousands of names. He also made the point that having those large numbers is, for all intents and purposes, meaningless.
Anyone can add names to their family tree. And many only do just (or only) that, regardless of whether they can justify relationships.
But so what! If you want to go back a few million years we can make a case that we are all related. In reality we can confidently only go back a few hundred years - perhaps 15 generations. Beyond the early part of the 16th century we are stretching credibility by listing ancestors or stating relationships. Few medieval records list the names of people, certainly true for the “common” people from whom most of us descend.
Many family historians want to latch on to the nobility which I think happens because only those few families published any kind of genealogical summaries. How many times have you seen someone’s tree that goes back to Charlemagne? That’s 30 to 40 generations.
Adam Rutherford poked a little fun about about relationships to the King of the Franks in a 24 May 2015 piece in The Guardian: So you’re related to Charlemagne? You and every other living European… He comments: “I am a direct descendent of someone of similar greatness: Charlemagne, Carolingian King of the Franks, Holy Roman Emperor, the great European conciliator. Quelle surprise!” He goes on to state, “This is merely a numbers game. You have two parents, four grandparents, eight great-grandparents, and so on. But this ancestral expansion is not borne back ceaselessly into the past. If it were, your family tree when Charlemagne was Le Grand Fromage would harbour more than a billion ancestors – more people than were alive then.”
The absence of true records of the greater proportion of the population over the centuries before about AD 1300 compels many people to attach themselves to those who have been named in formal documents. Seemingly, if you can trace a connection to any member of a European royal family then you are a descendant of Charlemagne (see Descendants of Charlemagne).
There is also an assumption that many members of ruling or royal families had scores of illegitimate children who somehow became the ancestors of so many of us. I seriously doubt that is true as there has always been a much larger number of people unrelated to those families. Their descendants would logically still make up most of the population today. Connections to any branch of royalty are often very tentative, perhaps even more like wishful thinking.
If you want to go back to Numero Uno in terms of human evolution then we can probably say we are all related. But that analysis is meaningless for family history studies. DNA may help us find or confirm some familial relationships within a few generations and among some close cousins but it won’t tell the whole story about our families and that is what we are really after, aren’t we?
There should be reservations even using DNA, assuming we could get samples from people as far back as the 9th century. One shares less than 1% of their DNA with their 6th great-grandparents which would make you wonder whether you can even truly demonstrate a blood relationship. The number is not even statistically relevant going back past 20 generations.
Going back to another post by James Tanner (Sourcecentric Genealogy), to conclusively show relationships or connections to past generations, one must work with bona fide historical records. Even some royal families’ trees or publication of them may be more fiction than fact so researchers must go beyond the summaries to find actual church or other records. And, again, any document dated earlier than the 14th century should be used with caution.
So, is everyone related to everyone else? Only in the most general, biological sense but not in any meaningful one with regard to family history!