psychic detectives
so called "King John" was LackLAND AND many many people supposedly descend from him
—there are a very large number of living descendants of King John Lackland (1166/7–1216), which makes the connection to many (or even most) U.S. Presidents unsurprising rather than some rare or conspiratorial “importance.”
King John had five legitimate children with his second wife Isabella of Angoulême (Henry III, Richard, Joan, Isabella, and Eleanor—all of whom had descendants) plus several documented illegitimate ones. His direct line continued powerfully through Henry III and the later Plantagenet kings (Edward I, Edward III, etc.), who had large families that intermarried with nobility and gentry. Over ~800 years (roughly 28–33 generations), those lines spread widely through the English population and its colonial offshoots.
No one has a precise headcount (genealogy records become incomplete farther back, and DNA/pedigree collapse means most people share many ancestors anyway). But solid estimates from genealogists and models put it in the millions to tens of millions worldwide, especially among people with British Isles ancestry:
A 2021 BBC analysis of royal descent models estimated ~2 million living descendants for Edward I (King John’s grandson, via Henry III). That’s already a huge number from just one branch one generation down.
For later kings like Edward III (John’s great-great-grandson), some models suggest he is an ancestor to a very large share—potentially nearly all people with English/British ancestry in the modern era, once you account for intermarriage and population growth. One study noted that a mid-20th-century English person would have ~80% of the early 13th-century English population in their family tree due to pedigree collapse.
Broader genealogical consensus (e.g., from experts like Mark Humphrys) is that millions of people worldwide have provable or highly likely descent from medieval English monarchs like John. Some informal estimates put the figure for those with English/British roots at 70% or higher in places like the U.S., Canada, Australia, etc.
In short: exponential growth + lots of surviving children in the early generations + massive intermarriage = a huge pool today. It’s the same reason why Charlemagne or William the Conqueror are ancestors to vast numbers of Europeans and their descendants.
Professional genealogists generally confirm that a large majority of Presidents have documented royal/Plantagenet ancestry—often through later kings like Edward III or Edward I, via “gateway” colonial immigrants in the 1600s–1700s. The exact “42/43” or “all but one” figure has some debate on verification for every single link, but it’s clear that most Presidents share this ancestry.
Most early U.S. Presidents (and many later ones) came from families with deep British colonial roots, and those colonial families were drawn from the same English gentry/nobility pools that carried Plantagenet blood.
Your earlier point about the millions (or tens of millions) of descendants is still 100% correct—and that’s precisely why the “all but one” pattern holds.
Shared demographic roots: With the exception of Van Buren (and possibly Eisenhower’s German/Swiss line), every U.S. President has British Isles ancestry, mostly tracing to colonial-era English, Welsh, Scottish, or Irish immigrants in the 1600s–1700s.
en.wikipedia.org
Those colonial “gateway” families were disproportionately drawn from English gentry and nobility circles—exactly the groups where King John’s descendants (via Henry III → Edward I → Edward III and their massive offspring) had spread by the 1300s–1500s.
Elite intermarriage + pedigree collapse: Once you’re in those networks, lines converge fast. Professional genealogists (e.g., Gary Boyd Roberts in books like Ancestors of American Presidents) have documented royal/Plantagenet descent for roughly two-thirds or more of presidents via verified sources. The d’Avignon project simply pushed it back to the specific Plantagenet king and included female lines.
It's not formally verified by the snobbish geneologists, but it's true.. But it's because everybody from that sampling , early American colonial, did come from the English Gentry. That King had millions and millions of descendants, so it seems.