A lot of our ideas about kings and castles and knights begin to emerge around the time of Charlemagne. This notion of being a Holy Roman Emperor, because he's able to provide protection to the pope. The pope says, hey, I'm going to say that you are continuing on the legacy of the Roman Empire. Now, as we'll see, and we cover in much more detail in other videos, the title of Holy Roman Emperor, or Emperor of the Romans, does not continue on with Charlemagne's descendants. But when you get to 962, Otto, who's a German king, is crowned Holy Roman Emperor again, and you continue to have Holy Roman Emperors all the way until 1806. Now, another major feature of the early Middle Ages, and you can see it on this map, is that Islam in the seventh and eighth centuries, it comes out of Arabia and is able to conquer much of the Middle East, Persia, North Africa, which you don't see on this map, and much of what we consider today to be modern-day Spain. And you can see it, you see the Caliphate of Cordoba right over here, you see the Abbasids here in the east, who also controlled much of North Africa.