Most recent common ancestor (MRCA) of people of European descent?
We know the claim that people of European descent are descended from everyone who lived during the time of Charlemagne and whose descendants have survived to the present day, as explained by the multiplication of ancestors with each generation going back in time and the pedigree collapse.
Experts also say that all Europeans today are descended from Europeans who lived 1,000 years ago. This means that figures such as William the Conqueror and Hugh Capet are probably part of all our family trees, even though this cannot be proven for most of us due to a lack of documentary evidence.
This sparked a very specific question in my mind: Who would realistically be the most recent historical figure to appear as a common ancestor in our (sometimes proved, sometimes theorical) family trees, as people of European descent? Would it be someone from the year 1000? From the year 1100? 1200? Which rulers or other famous figures could we name without taking too big a risk?