Ever heard the cliche that we're all related? That isn't just a facile "we are the world" sentiment -- we are all related, and more closely than you might think. The numbers suggest that less than 1,000 years ago, everyone on the planet at the time is theoretically among your ancestors.
The chart below, and in the next three posts, shows the approximate number of ancestors of a baby born in the year 2000 CE. The number doubles each generation (2 biological parents, 4 grandparents, 8 great-grandparents, etc.), with the chart using four generations per century, a fairly conservative figure. Not scientific, but somewhat thought-provoking.
(numbers calculated on Excel -- the lazy person's friend!)
By doubling the number of direct ancestors for each generation, you hit the half-million point around the year 1525.