Family researchers have long known that if you go back far enough, everyone with a European connection ends up being related to Charlemagne. The concept was laid out scientifically more than a decade ago. Now Coop and University of Southern California geneticist Peter Ralph have come up with the evidence. Their findings were published on Tuesday in the open-access journal PLOS Biology.

“Anyone alive 1,000 years ago who left any descendants will be an ancestor of every European,” the researchers say in an FAQ file about their study. “While the world population is larger than the European population, the rate of growth of number of ancestors quickly dwarfs this difference, and so every human is likely related genealogically to every other human over only a slightly longer time period.”

Those conclusions are based on a survey of genetic sequences from more than 2,000 individuals spread from Ireland to Turkey.