The Carolingian Empire was the greatest superpower of its day. It was unmatched by its rivals, and its most famous leader, Charlemagne, was revered by the papacy for his efforts to spread Christianity. At its height, the empire stretched from Spain to Denmark, and from Brittany to Austria. Europe would not see another empire of its size until Napoleon. Under Charlemagne, all seemed well, until his grandsons unraveled everything.
The Franks had not developed the concept of primogeniture, meaning their lands had to be divided equally amongst all of their sons. Charlemagne was lucky, for he had only one legitimate heir and so his empire remained intact after his death. His son Louis, however, fathered three sons early in his life and was urged to make plans for his succession. He divided the empire among the three, but shortly thereafter he fathered a fourth son by his second wife. He redrafted his will to include his youngest, causing his first three sons to rebel against him. The empire was plunged into a chaotic civil war.
Lying in wait was an enemy who had been unsuccessful in breaching the coastal defenses to the empire under Charlemagne. With the armies of the Franks engaged elsewhere, the Vikings made their most bold advances on major cities that had once been thought untouchable. First Nantes in 843 A.D., then Paris in 845 A.D. From there the Franks suffered disastrous defeats against the Vikings and would not be rid of this new foe for over a century.
The Franks should have seen it coming.
There is a similar narrative from earlier in history that parallels the woes of the Frankish Empire. In the third Century, the Roman Empire experienced many crises, including one in the British Isles that saw many Britons flee into the region of Brittany, in modern day France. Taking advantage of the situation, seaborne raiders pillaged the coasts of the Roman Empire from Normandy to Aquitaine. Their raids further destabilized the region and helped lead to the eventual collapse of Rome’s authority along the Atlantic coast. These raiders were none other than the Franks.
Indeed, the Franks had developed a rich maritime tradition in the Baltic, one which they later abandoned in favor of land-based conquests. Their absence from the Baltic region as a powerful seafaring force is arguably what allowed the Vikings to develop their maritime hegemony over the other Germanic tribes. Four hundred years after they had helped usher in the demise of an empire, the Franks fell victim to the same style of assault that helped to bring about their own empire’s demise.
Perhaps it was just history repeating itself, or perhaps it was divine retribution.