The received wisdom concerning the fragmentation of the Western Roman Empire has undergone a total volte-face over the last century. From Völkerwanderungen, movements of entire peoples wearing furs and horned helmets violently invading Roman territory and carrying out ethnic cleansing, we are now expected to believe in "Elite transfers", small numbers of immigrants who came peacefully and amicably and took control with the full approval and cheerful willingness of the locals, and who apparently so impressed these indigenous populations that they all wanted to walk and talk like their new wonderful, kindly and not-at-all-oppressive rulers. This view is invariably accompanied by much sociological cant around concepts of "class", "status" and "identity" - the latter, so we are supposed to accept, being something which whole communities of mid-first-millennium peasants could and did suddenly change at the drop of a hat.
When there are two such opposed viewpoints, you can be sure that the truth is to be found midway between the two. Peter Heather, combining literary sources, archaeology and modern understanding of population movement and change, partially accepts some of the contemporary ideas, but persuasively argues for large scale migrations having often played a part in the changes across Europe in the period c. 400-1000. As Heather drily notes about the Slavs for example, but which equally applies to all the other invaders of the period, "Their military effectiveness makes it extremely improbable that [the changes] came about just because the indigenous populations thought it would be great to become a Slav."
It's a huge book, often repetitive, and certainly fairly hard going, but it's a well argued presentation and an extremely important contribution to the understanding of this period of European history.
This is one of those scholarly books that can forever change your perception of a crucial period in history, re-framing it so to speak. It is fascinating and essential, but so rigorously argued that it is very difficult to read and chock full of deadly dull scholarly proofs and arguments. Most importantly, rather than a narrative, it is strictly analytic, far closer to multi-disciplinary social science than history. I would estimate that half of the book is a great joy to read and the other half a dry slog for the determined. The prose is, to put it mildly, dense.
Heather begins with an extremely terse discussion of the sociology of migration. In the past, he argues, scholars (often backed by iffy primary sources) promoted a "billiard ball approach", in which migrating groups knocked others out of the way, perhaps eliminating them by ethnic cleansing or forced absorption as slaves or serfs. Archaeological findings, however, belay this view, indicating instead that groups were far more amorphous, like coalitions with a charismatic leader at their center that grew like a snowball as it gained politico-military momentum. Language and ethnicity were more fluid than assumed, Heather argues, adopting that of the military/economic elite or later perhaps that of the occupied territory. This paragraph cannot do justice to the subtlety and cogency of Heather's arguments, which are assessed against primary sources, archaelogical evidence, and socio-historic examples such as the experience of the Boars as they migrated North to avoid British colonial rule. (From a motley crew, the boars united into highly organized military force and quickly beat the Zulus into submission.)
At the fall of the western Roman empire to germanic tribes (i.e. Goths) in the 5th C CE, migration patterns were changing. From disorganized bands that were seeking to exploit Roman wealth - via border raids, trade, mercenary wages, and diplomatic subsidies as part of Roman foreign policy - they had become very large political entities that included women and children (increasing their numbers vis-a-via warriors by 4x). The earlier groups had been living at subsistence levels as itinerant farmers perpetually in search of fertile ground, beginning their movements with trickle of early explorers (in 2C CE) that became a torrent by 5C. But they were also fleeing the Huns, and later the Turkic Avars, who established powerful military empires in central Europe that were based in pillage and charismatic leaders such as Attila. The new entities were far more organized in their command structures, were learning superior agricultural techniques (to replenish soil nitrogen via turning over rotten plants and crop rotation), and adopting cutting-edge military technologies and tactics.
Similar tribes (i.e. Angles and Saxons) invaded Britain in large enough groups that they displaced the local elites and destroyed their economic systems; eventually, they instilled their language into the local populace, as women could teach the children their original languages, they replaced local languages, including Latin and Celtic. This was a pattern that was often repeated in Europe until 1000 CE, when the principal language patterns that survive with few exceptions (Turkish in Anatolia being a rather big one) to this day.
As western Roman economic structures declined, new power centers arose in northern Europe for the first time, in 7 C CE. Though the level of socio-economic and political sophistication were far below those of the Romans, the new entities were proto-modern states nonetheless. They learned to create military organizational structures, monopolizing the means of force in order to maintain the elites that eventually became entrenched in land ownership and hence became the grand royal and aristocratic families that ruled for the next 1500 years. Heather also covers the Vikings and Slavs; the origins of the latter remain murky and unknowable from the archaeological record. The Slavs, interestingly, conquered much of central Europe because elite Germans seem to have migrated West, leaving poorly armed and disorganized Germanic peasants, who were then absorbed into the newly dominant Slavic elites and tended to adopt their languages. Due to their lack of ability to tax and build viable cities, these semi-nomadic groups faced inherent limits: once they expanded to large size based on pillage and forced tribute, they could no longer pay their forces enough to keep them together and so these mini-empires disintegrated; so the Carolingians, Merovingians, Ottonians, and scores of others succeeded each other a few generations after the charismatic founder disappeared.
It was only later, around 1000 CE, when the empires became more sedentary with larger surpluses of wealth (due to their adoption of more productive agricultural techniques), which paid for the construction of the massive fortified castles that still dot the European landscape; standing armies that could better protect subjects; and more diversified economies, that empires were able to grow more stable. It was also at that time that the various linguistic groups had come to occupy the places that they occupy today - thus, the basis of what became European nation states was more or less set. Invaders later only rarely dislodged these language groups, but rather were absorbed in their turn. There were also extremely sophisticated trading networks that sprung up, bringing northern goods such as furs to the most sophisticated civilizations of the time, the Islamic states, whose silver financed a great deal of the economic expansions in the North.
If this sounds rather abstract, so is the book. It is often not fun to read. However, there is absolutely no question that this is a masterpiece of scholarship that will define the field for a generation. Heather is brilliant, writes beautifully, and often with wonderfully playful humor. (He refers with frustration, for example, to the fact that his students no longer know what he means when referring to black and white television. It got me to laugh.)
I recommend this book for those with the personal interest to persevere through very difficult scholarly arguments. It is the natural follow-on to Heather's equally brilliant (and far more fun) Fall of the Roman Empire. If you wish to understand what made up the extraordinarily diverse language in all of their modalities from 400 to 1000 ce, this is a book for you. I am glad I read it, but it was, well, very challenging and often failed to keep my attention.