“You see before you the wrath of the Lord breaking forth. . . .There is naught but towns emptied of their folk, monasteries razed to the ground or given to the flames, fields desolated. . . .Everywhere the strong oppresseth the weak and men are like fish of the sea that blindly devour each other.”

These words were written by the bishops assembled at the Council of Trosly in the year 909 in what is today northeastern France. It had been about four-and-a-half centuries since the fall of the western Roman Empire, and about 100 years since the Viking invasions of the region had begun. The bishops were desperate to curtail the mayhem brought by the Northern barbarians. Such desperation was a hallmark of this era of extreme violence and disorder in Western Europe, a continent besieged from the North by the Vikings, from the East by the Hungarians, and from the South by the Muslim invaders.

The Vikings were among the original Germanic tribes, predating even those of what is now Germany proper, which was populated by Celts before they were conquered by the Germanic warriors of Denmark. The Vikings were, famously, a seafaring people, whose ships could cross oceans and then sail down rivers hundreds of miles into the interior of the European continent. Over generations, their raiding excursions took on a more permanent character, evolving into conquest and settlement. The Vikings became as much the vanquishers of the soil as of the sea.

As the invaders adapted themselves to their new roles as territorial rulers and settlers, they assimilated into both the gene pools and the folkways of the peoples they subjugated. In the east, they married Slavs and birthed a new people called “the Rus” — meaning, from their Viking heritage, “men who row.” In the West, the Angles of Denmark settled Northumbria and East Anglia, the region of the British isles that would expand over the centuries into the nation of England. And they conquered a vast region of the Frankish kingdom, putting the fear of the end of the world into the bishops at the Council of Trosly. A couple of years after the Council, the Norsemen would be granted sovereignty over the region, which would be come to be called “Normandy” in their name. The Normans would exchange their native Scandinavian tongue for the French language, adopt Frankish customs and agricultural practices, marry into Frankish families and become, in every way, “French.” Then, a century-and-a-half later, the Normans would cross the Channel, conquer their Anglo-Saxon cousins and rule England as well.

This was a particularly violent stage in the evolution of feudalism in Europe, a social order characterized by fragmented sovereignty and private war-making. For a thousand years it prevailed over the continent, until it evolved into the system of modern nation-states we live in today.