Carolingians

After Charlemagne died, his son Louis inherited the empire, and then Louis's three sons divided his empire between them. One son took the west (mostly modern France), and one son took the east (mostly modern Germany) and one son took the middle. The middle son didn't last very long, before the other brothers killed him. Although there was a lot of fighting between the two brothers and their children and grandchildren for a long time, nobody really ever succeeded in putting together a large empire like Charlemagne's again. They each ruled small parts of his empire. Really this was a lot like what happened to the empire of Clovis, the Merovingian.

But the kings who held Germany kept Charlemagne's title of Holy Roman Emperor, and the rulers of Germany were known as the Holy Roman Emperors for the next thousand years (until Napoleon).

The Capets (France)
The Holy Roman Emperors (Germany)
Main medieval history page