At the start of the first millennium, western Eurasia can be divided into three broad east-west zones when measured in terms of what we would now call ‘development’. This was a world of almost no literacy at all, but an enormous amount of archaeological investigation undertaken since the end of the Second World War has made it possible to sketch in at least the outlines of prevailing social and economic structures. There were overlapping liminal regions in between, but the basic pattern of life within each of these zones was distinct. The first lay largely west of the river Rhine and south of the river Danube. The second, central European zone stretched from the Rhine to the eastern hinterland of the river Vistula, together with southern Scandinavia and some outliers east of the Carpathians. The third zone encompassed vast tracts of what is now eastern Europe, beyond the Vistula and north of the Carpathians.

In zone one, comparatively developed agricultural techniques had already generated relatively dense populations. The overall level of economic integration is debated, but the evidence for economic complexity is relatively plentiful. This was the home of the so-called ‘Oppida culture’, some of which were well-established settlements of several thousand individuals. There is also plentiful evidence for non-agricultural, non-subsistence economic activity: wheel-made pottery, relatively advanced iron-working, and even some use of coinage. Exchange, likewise, was relatively intense, as demonstrated, not least, by a wide array of Mediterranean imports. Roman historical sources also confirm that the largest and most stable political structures of contemporary non-Mediterranean Europe were located in the same region.

Zone two was largely dominated by speakers of Germanic languages, but ethnicity is beside the point. Compared to zone one, agriculture was substantially less intensive. The balance was more towards pastoral farming, and lower agricultural yields generated lesser population densities and highly dispersed settlement patterns. Individual settlements, usually no more than hamlets, were also not occupied for more than a generation or two, reflecting an incapacity to maintain the long-term fertility of arable fields. Economic complexity was correspondingly limited. There was some iron-working, but less than in zone one, pottery was handmade and only locally distributed, and there is little evidence for trade and exchange. On the political front, too, prevailing structures were for the most part small scale. From Tacitus’ histories and Germania, there were more than 50 basic political units distributed north of the Alps between the Rhine and Vistula, and these were not ancient fixtures of an unchanging political landscape. Existing units could be destroyed, and new ones form. Larger coalitions could occasionally be put together by individuals of great charisma, but these rose and fell with great rapidity, showing no capacity to outlive their founders. Groups on the western and southern fringes of this region interacted freely with those of zone one, generating a border region which combined patterns from both zone one and zone two, but, this aside, life in the second region was substantially distinct.

The same is true of zone three. This vast expanse of territory was home to populations speaking a variety of Slavic, Baltic, and Finnic languages, or their immediate ancestors. Iron was used, but life here was simple in the extreme. Settlements were smaller and still more dispersed than in zone two, reflecting still less productive agricultural regimes, supporting, again, much lower overall population densities. And despite more than 50 years of periodically intense archaeological investigation (especially during the Soviet era), zone three remains of this era have produced no sign of trade contacts with outside regions, and no clear indicators of any economic complexity beyond basic, subsistence-level farming. There is also no sign at all of sociopolitical structures that were anything but highly local. So simple and unchanging are its remains, in fact, that it is often impossible to locate finds any more precisely than to a very broad period between circa 500 BC and 500 AD.

Recognising the degree of overarching disparity which prevailed across western Eurasia around the birth of Christ, provides a clear starting point for thinking about exactly how much had changed by the year 1000. Politically, perhaps the most dramatic transformation was a fundamental shift in the geographical centre of interregional power. By the start of the first millennium, Rome mobilised the populations, economic resources and technological expertise that had developed across the Mediterranean since the Bronze Age. This enabled it to generate the military and political capacity which made it the dominant imperial power of western Eurasia, quickly swallowing up most of the populations of zone one. By the late first millennium, the centre of empire had shifted decisively northwards. The eighth and ninth-century Carolingian Empire encompassed parts of both zones one and two, and the Ottonian Empire – the dominant political force of tenth-century Europe – was firmly based on lands which had been home only to the small-scale, loose political structures of zone two a thousand years before. The rise of these empires fundamentally overturned the ancient balance of strategic power. At the start of the first millennium, the Mediterranean-based Roman Empire had dominated the broad arc of Europe within its reach. By its close, the north had become politically dominant and was predatory now upon the still substantial wealth of Mediterranean Europe, with both Carolingian and Ottonian Empires quickly extending their reach south of the Alps.

Simultaneously, the final two centuries of the millennium saw the emergence of the first large-scale, reasonably durable state-like structures in eastern Europe. So-called ‘Great Moravia’ (in modern Slovakia) was a precocious phenomenon of the ninth-century destroyed by Magyar intrusion. But the tenth-century saw the emergence of durable state structures in Bohemia, Poland, and along the river axes of western Russia and the Ukraine between Novgorod and Kiev. In the year 1000, these structures remained at a relatively early stage of development, with relatively tightly organised dynastic heartlands surrounded by loosely-governed outer territories, which were often swapped between the three dominant dynasties (respectively the Premyslids, Piasts, and Rurikids).

But in their dynastic cores, historical and archaeological sources both document the effects of substantial and continuous governmental authority. Population densities increased as labour was imported from outside to step up agricultural production, while organised public works were undertaken both for defence and for ideological projects, such as large-scale church construction. The famous Tithe Church was constructed in Kiev in the 980s, while, on a state visit to Poland in the year 1000, the Holy Roman Emperor Otto III inaugurated a new church province for the Polish kingdom consisting of an archbishopric at Gniezno and two dependent dioceses.

These political developments were matched economically. Considerable inequalities remained, which is why Carolingian and Ottonian elites wanted to exploit Mediterranean Europe. Nonetheless, the first millennium AD saw a substantial erosion in prevailing degrees of economic disparity. All pre-modern European societies were fundamentally agricultural, so that evolving farming technique lay at the heart of economic transformation. Large forests still covered much of central and eastern Europe in the year 1000, but pollen core analysis shows that the preceding few centuries had seen much land cleared for arable cultivation. Just as important as felling trees was developing agricultural technique.

The great problem with north European soils, compared to their Mediterranean counterparts, is their heaviness, making it much more difficult to turn them over properly, so that rotting weeds and crop residues can maintain crucial nutrient levels over the long term. The Mediterranean region provides fewer agricultural assets overall, but they are much easier to work, allowing for the early maximisation of exploitation and population which underpinned Roman dominance of western Eurasia at the time of the birth of Christ. The problem in the north was eventually resolved by the heavy plough: a massive iron ploughshare mounted on a four-wheeled wagon pulled by anything up to eight draught animals. Such ploughs provided the requisite power, but were massively expensive (not least in terms of winter fodder for the plough teams) and required the coordinated exploitation of peasant populations and agricultural assets in centrally organised estates: the classic medieval manor.

This form of intense arable farming had not spread widely across eastern Europe by the year 1000, but its greater productivity already underpinned the Carolingian and Ottonian Empires. By radically increasing levels of food production, centralised manors, which emerged in Frankish heartlands by the eighth-century at the latest, greatly increased population levels in northern Europe: the fundamental explanation for the northwards shift in the European balance of strategic power across the first millennium. From there, the new agricultural patterns began to spread into at least the core territories of the new east European states in the tenth-century, even if there were many stages of development to come, not least with the recruitment of hundreds of thousands of Germanic peasants by east European dynasts in the eleventh and twelfth-centuries. But food production had already increased dramatically in their core zones by the year 1000, generating extra population and wealth which played a fundamental role in sustaining the new dynastic states.

Similar observations apply to other indicators of economic complexity. Settlement size had long been on the increase in those parts of the old second zone now dominated by the Ottonian Empire. In the last two centuries AD, however, much larger settlements began to appear in eastern and northern Europe, if again primarily in the dynastic cores. Great Moravia generated some astonishing stone remains, including the largest church built from scratch in all of ninth-century Europe, at Mikulcice. In the tenth-century, fortified town-like structures, interlocking with larger and more concentrated patterns of rural settlement, can be found in the core regions of all the new states of eastern Europe.

These new settlement patterns are matched by increasing evidence for more complex patterns of production and exchange. The 9th and 10th centuries saw massive imports of Muslim and west European silver coins into eastern Europe, reflecting an explosion in long-distance trade. Patterns of more local production and exchange likewise changed out of all recognition. Wheel-made, commercially-produced pottery replaced the handmade wares which had previously prevailed across eastern Europe. As elsewhere, this probably reflects a more general move towards a situation in which agricultural populations were exchanging the larger surpluses made available to them by increasing yields for commercially produced superior products, rather than making nearly everything themselves. Again, we’re certainly talking about a relative development. Eastern Europe shows nothing like the intensive cloth-working industries which were already emerging in Flanders by the year 1000, and both production and exchange were more intense in Ottonian central Europe than further east. But the complete disparity of a thousand years before had given way to a trajectory of economic convergence.

This extended into cultural spheres as well. The first written form of any Slavic language was generated in the ninth-century to translate the Bible. And by the later tenth-century, the use of written Slavic for ecclesiastical, and of Greek and Latin for administrative documents was becoming widespread across eastern Europe. By this date, too, the now standard Christian European cultural infrastructure of episcopal and monastic schools, equipped with a common repertoire of books and similar training regimes, was very well-established in zone two, and beginning to replicate itself in the old third zone. Fascinatingly, while the process of establishing this common repertoire had originally drawn very heavily on the scholars and library resources of the Mediterranean, their mobilisation to generate a new, common pattern of Christian knowledge was a north European enterprise. Its outlines were established by Charlemagne and the scholars he assembled at court and at a series of key northern monasteries and episcopal sees in the later eighth-century. And from there, essentially the same stock of books and Christian educational training spread to hundreds of diocesan centres and Benedictine-type reformed monasteries right across Latin Christendom. Many of the intellectually most vibrant centres of Christian culture were still located much closer to the Mediterranean, but the density of north European Christian educational centres, key transmitters of the new literate culture, would have astonished a Roman imperial observer of the first-century AD.

By the year 1000, at both state and regional level, political structures had emerged across central and eastern Europe which would not only shape the remainder of the middle ages, but would also, much later, be claimed by their various partisans to be direct ancestors of the nation states of nineteenth and twentieth-century Europe. These structures proved so durable because – thanks to the transformations of the first millennium – they were based upon economic, demographic, and cultural structures of much greater stability than anything previously seen. In a very real sense, Europe as we know it – a zone of relatively intense political, economic, and cultural interaction – first came into existence in the millennium after Christ.

It is not possible to offer anything more than an outline here, but my own understanding of the main drivers of change behind this process is stimulated by three more precise observations. By the fourth-century AD, first of all, a considerable erosion of the original disparity between zone one and zone two was already visible. In areas immediately adjacent to the Roman Empire, a revolution in agricultural technique was already sustaining a considerable population increase, together with larger and longer-lived settlements, both of which reflect higher crop yields and better arable fertility. Larger and more stable political structures were also evident in historical accounts of the empire’s evolving diplomatic relations with its semi-subdued European clients just beyond the frontier. Literacy, too, spread outside the empire, the first written form of any Germanic language being created by Ulfilas in the fourth-century in Gothic lands, and some of the empire’s clients, again particularly Goths, were confronting the problem of how to respond to the challenge of Christian conversion, recast now as a Roman imperial religion. But while all this was unfolding in zone two, there is no evidence at all for any major economic, political, or cultural transformation in zone three before c500 AD. In the first half of the millennium, the erosion of disparity did not unfold evenly, but was concentrated in zone two, and particularly among its fringe groups who had been in constant contact with Roman imperial power in the intervening centuries.

Second, long-established trajectories of evolution in this second zone collapsed more or less simultaneously with the disintegration of Roman imperial power in zone one. In c375 AD, the new developmental traits now increasingly characteristic of zone two stretched from the Rhine and southern Scandinavia to the Vistula in the north, and, further south, incorporated both the Carpathian basin and the North Pontic littoral. One hundred and fifty years later, after the west Roman Empire ceased to exist, continuity along the same lines of socioeconomic and political-cultural development persisted only in zone two’s westernmost fringes, between the rivers Rhine and Elbe, in southern Scandinavia, and in the Middle Danube basin. Everywhere else, centuries-old trajectories of development broke down completely, with patterns of life now resembling their much simpler counterparts typical of zone three. That so many structures of life should have collapsed simultaneously, in both zones one and two, strongly suggests that the two had become tightly bonded in the first half of the millennium.

Third, the later phases of eroding disparity did not operate evenly either. When transformation finally began in zone three, it was again concentrated in those regions most closely in contact with societies already displaying more developed patterns of life. Three of the first Slavic states of the ninth and tenth-centuries arose in the immediate hinterland of the Carolingian and Ottonian Empires: Moravia, Bohemia, and Poland. The point also holds true – if in a slightly different way – for the network of Rus communities between Novgorod and Kiev. These settlements had important links with the Byzantine Empire, but also – as both coin finds and written sources emphasise – with the highly-developed Islamic caliphates of the near east. A contact model also explains the southern Scandinavian evidence. This region was different in that parts of it had shared in the earlier transformations of zone two in the Roman period, without being affected by subsequent processes of culture collapse. So it is not surprising to find evidence for larger political structures here, especially in later eighth-century Denmark in the form of the Gottfrid/ Horic dynasty. But this Danish proto-state disappeared quickly in the ninth-century, and new kingdoms (more directly ancestral to the high medieval states of the region) emerged across southern Scandinavia only in the tenth-century. Thanks to the development of sea-going naval technology in the eighth-century, these tenth-century kingdoms were also constructed on the back of two centuries and more of steadily intensifying, and unprecedented contacts between Scandinavia and the rest of more developed Europe.

Taken together, these three observations suggest prima facie that contact between more and less developed parts of Europe played a major role in the overall story of eroding disparity. This basic suggestion is only strengthened by closer examination of the precise operation of the range of contacts being generated in these hot zones of interconnection.

Most often discussed, a whole series of economic exchanges sprang into existence. In the first three centuries AD, Rome’s legions, massed on the frontier, represented a huge source of regular demand for foodstuffs and other raw materials (particularly wood and leather). A Roman legion, five thousand strong, required 225 tonnes of grain and 13.5 tonnes of fodder a month. Sometimes, soldiers just took what they wanted, but more often they instituted regular supply contracts with nearby populations on both sides of the frontier. The appearance of large-scale iron working in central Europe in the same centuries has also been associated with Roman demand, and well-documented too is the luxury amber trade operating from collection points on the southern shores of the Baltic Sea.

A recent reflection of the scale of this activity has emerged in the form of a whole series of causeways in what is now northern Poland. In the second half of the millennium, furs and slaves went west and south from Scandinavia and the broader expanses of the old zone three, often in the hands of Scandinavian middle men putting their new naval expertise to good use, to rich centres of demand in western Europe and, especially, the Islamic near east. The furs and slaves are archaeologically invisible, but hundreds of thousands of the western and above all Islamic silver coins that came back in return are still extant, and many more must have been melted down in the interim.

On a simple level, these new trade links introduced unprecedented wealth into zone two in the Roman period, and zone three later on, but that is only half the story. Once the new wealth flows began, these generated their own transformative multiplier effect, in the form of struggles within the less-developed societies to control the profits. In the Roman period, trading rights were a privilege, granted only to highly favoured frontier clients. The point emerges still more clearly in the second half of the millennium. Islamic silver coin finds are not evenly distributed, but concentrate in three broad clusters: one up and down the river systems of western Russia and the Ukraine, a second distributed across parts of Scandinavia, and a western cluster on the territory of modern Poland, with an extensive, largely find-free area in between. Given that Islamic sources tell us that the Rus raided westwards for slaves, and “western” Slavs eastwards, this blank space surely reflects the region from which most slaves were taken. And it was in precisely these silver-rich zones that the new states – Poland, Bohemia and the kings of Rus – appeared in the tenth-century. This cannot be accidental. The new dynasties of the ninth and tenth-centuries were the prime beneficiaries of the new flows of trade wealth, which means that they were also the groups who organised themselves best to profit from it: by taking slaves and furs directly, and/or by controlling other groups who did the primary job of extraction.

These lines of thought also help explain the strange fall and rise of state structures in southern Scandinavia. Such was the flow of silver into the Scandinavian Baltic in the ninth-century, much of it being recycled (as we know from historical texts) to buy military support, that political competition between existing elites there intensified massively. This explains both why the old Gottfrid/Horic dynasties were extinguished, and why others – in part to escape the intensity of the competition – later shifted their centre of operations to northern Francia and the British Isles. It was only when the inflow of new wealth calmed down, in the tenth-century, that aspirant dynasties could rebuild a more stable form of control. New flows of trade wealth not only provided the raw material for greater social differentiation but, perhaps more important, generated intense competition among local participants to maximise their share of the profits.

The same kind of two-level impact model also applies to other dimensions of contact between more and less developed societies. In both halves of the millennium, the larger, imperial states regularly paid diplomatic subsidies to clients beyond the frontier. As in the modern world, these were designed to prop up regimes perceived as generally sympathetic to imperial agendas, and the client kings obviously benefited not only from the prestige of imperial connections, but from the extra powers of direct patronage the recycled subsidies made available to them to strengthen their political positions. Again, we are dealing not only with the inherent capacity of new wealth to prompt social transformation, but also with uneven distribution mechanisms which allowed certain individuals and groups to gain preferentially. And, as with the flows of new trade wealth, there was intense competition between potential clients for these subsidies.

Military contacts had equally dramatic effects. It is a famous old story that Arminius, who led the Germanic coalition which destroyed Varus’ three legions in the Teutoberger Wald in 9 AD, had previously served in the Roman army, learning there some of the techniques employed in the battle. Much easier to quantify are the effects of transfers of military technology. Roman mass production techniques for weaponry, above all swords, were quickly copied in zone two in the first half of the millennium, which, combined with new trade wealth and diplomatic subsidies, led to a recasting of political authority. Political power eventually became so closely associated with successful war leadership by the late Roman period, that all the contemporary Germanic words for political leader (unlike older analogues) originally meant “military commander”. New military technologies and organisation allowed emergent dynasts to monopolise the benefits of new wealth flows, both of which derived from contacts with more developed Europe, and lay at the heart of the political revolution that unfolded across most of zone two in the first half of the first millennium.

The combined effects of similar kinds of contact are even more visible in the subsequent political transformation of zone three. Charlemagne’s famous Capitulary of Thionville in 805 already banned exports of the latest military hardware – coats of mail (lorica) – east of the Elbe into Slavic territories. But they clearly continued, because the military contingents sent by the new kings of Poland to assist the Ottonian emperors of the late tenth-century are explicitly described as loricati, which helps explain something important about this new kingdom. In the course of its emergence, a series of long-established, large ‘tribal’ (for want of a better word) hill-fort refuges were replaced by much smaller garrison forts across its core dynastic territories. This used to be understood as a long, slow process of social evolution taking several centuries, but recent dendrochronological evidence demonstrates that change was dramatic. All the new garrison forts were constructed within a few years in the second quarter of the tenth-century. This was not so much slow socioeconomic evolution, as sudden conquest. As the Arab written sources confirm, the Piast dynasty used the new wealth it derived from the fur and slave trades to build up professional, well-equipped forces which were then used to establish a new level of domination over what rapidly became the core territory of its kingdom.

There are other dimensions of contact between the more and less developed parts of the region that are well worth mentioning too. Raiding adjacent economically richer territories was a standard mechanism for bringing new wealth into less developed Europe in both halves of the millennium. And, again, the profits of raiding were not evenly distributed. The new dynasts of non-imperial Europe could also mobilise the natural resentment generated by the more occasional, but much more violent, imperial campaigns which responded to such raiding, about once in a political generation on each sector of Rome’s European frontiers, to build greater political solidarity. In one telling example, the Moravians captured two sons of the Carolingian magnate who had previously been in charge of their frontier region. They cut off the sons’ tongues, right hands, and genitals in a highly symbolic act, reflecting their perception of the dishonesty and faithlessness of the father’s actions, and their hopes that his line would disappear forever. Even if it is generally hard to measure for the past, modern analogues suggest that general resentment at high-handed violence of imperialist neighbours would have been a powerful phenomenon. Cultural transfers, too, helped advance the processes of state formation which were central to the steady erosion of disparity across the European landscape. Not least, in the final centuries of the millennium, Christianity licensed – even commanded – converted dynasts to suppress the highly local pre-Christian cults which would otherwise have continued to be a force for separatist fission within the emergent kingdoms

There are additional dimensions of interaction that could be examined, and even those explored here have other dimensions of complexity, but I would argue that the kind of dynamic centre-periphery model laid out here goes a long way towards explaining the chronologically and spatially uneven erosion of disparity which characterises first millennium European history. Actors in more developed parts of the European landmass didn’t just ‘do things’ to passive recipients in less developed regions. But the more developed did initiate a series of dynamic new relationships with their less developed neighbours, which provided a general stimulus towards development in the periphery, and from which some groups were much better placed to profit than others. And it was around those who profited most – the new dynasties and their chief supporters – that new state structures gradually formed. What we are looking at, in other words, is a precocious analogue to the processes of globalisation which have become so familiar in the last generation or so of contemporary world history.

This essay originally appeared under the title ‘Empire and Development in First Millennium Europe’ in ‘The Return of Geopolitics: Perspectives from the Engelsberg Seminar’, Bokförlaget Stolpe, in collaboration with Axel and Margaret Ax:son Johnson Foundation, 2016.