An historical work on the early medieval German armies from the division of the Carolingian Empire under Charlemagne to the rise of the German or Holy Roman Empire. The text examines in detail the period of the Saxon Wars and the Crusades, including the rise of the Teutonic Knights.

It deals with the religious and political upheaval that shook Germany in the early 11th century, civil war, campaigns in Italy, and the temporary occupation of Rome by Henry IV, as well as the successes of the Teutonic Knights and the Minsterials – the knights who were serfs.