Their union under the vigorous rule of the great Frankish chief whom the French call Charlemagne, was at best nominal and partial.

The Holy Roman Empire, which he founded in the year 800 by a mystically vague compact with the Pope, was never a close bond of union, even in his stern and able hands.

Under his weak successors that imposing league rarely promoted peace among its peoples, while the splendour of its chief elective dignity not seldom conduced to war.
Next, feudalism came in as a strong political solvent, and thus for centuries Germany crumbled and mouldered away, until disunion seemed to be the fate of her richest lands, and particularism became a rooted instinct of her princes, burghers, and peasants.

Then again South was arrayed against North during and long after the time of the Reformation; when the strife of creeds was stayed, the rivalry of the Houses of Hapsburg and Hohenzollern added another cause of hatred.
As a matter of fact, it was reserved for the two Napoleons, uncle and nephew, to force those divided peoples to comradeship in arms.

The close of the campaign of 1813 and that of 1814 saw North and South, Prussians and Austrians, for the first time fighting heartily shoulder to shoulder in a great war--for that of 1792-94 had only served to show their rooted suspicion and inner hostility.