Charlemagne and His Successors. The Carolingian dynasty of the Franks ruling in France, Belgium, and Germany grew stronger during the 8th century. Charles Martel defeated Muslim invaders at Tours in 732. Charlemagne built a substantial empire by 800. He helped to restore church-based education and revived traditions of Roman imperial government. The empire did not survive Charlemagne's death in 814. His sons divided the territory and later rulers lacked talent. Subsequent political history was marked by regional monarchies existing within a civilization with strong cultural unity initially centered on Catholic Christianity. French, German, English, and other separate languages emerged, providing a beginning for national identity. The rulers reigning in Germany and northern Italy initially were the strongest; they called themselves holy Roman emperors, but they failed to create a solid monarchy. Local lords and city-states went their own way.