But the effeminacy of the people, especially of those in the higher ranks, made them the creatures of the army that protected them.

In some cases, the Emperor himself was selected by the army, or by the Pretorian Guard in Rome; and sometimes the guard removed an Emperor of whom it disapproved by the simple expedient of killing him.
After the fall of the Western Empire in 476, when Rome was taken by Odoacer, a condition of confusion, approaching anarchy, prevailed throughout Europe, until Charlemagne founded his empire, about 800 A.D., except that Constantinople was able to stand up against all outside assaults and hold the Eastern Empire together.

Charlemagne's empire united under one government nearly all of what is now France, Germany, Austria, Italy, Belgium, and Holland.

The means employed by Charlemagne to found his empire were wholly military, though means other than military were instituted to preserve it.

He endeavored by just government, wise laws, and the encouragement of religion and of education of all kinds to form a united people.