We don't have conquerors and kings anymore, in most parts of the world. The common ancestor would probably have to be the ancestor of a very successful nation

We don't have conquerors and kings anymore, in most parts of the world. The common ancestor would probably have to be the ancestor of a very successful nation that would rule (a big part of) the world, and no current world ruling nations let their governors reproduce at will, like they did in the past. Currently the world is full of Genghis Khan descendants, but also, there are no Genghis Khan equivalents anymore. Simply remember the Monika Lewinsky scandal.