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Migration and the End of Empire

Peter Heather —

However you line up the different factors involved, there’s no doubt that immigration played a major role in the unraveling of the western half of the Roman imperial system. By the end of the fifth century AD, from Anglo-Saxons north of the Channel to Vandals and Alans in North Africa, the vast majority of the ex-western imperial landmass was ruled by dynasts at the head of warrior groupings who had lived outside its borders when the century began. For some prominent modern commentators, from Boris Johnson and Niall Ferguson to Pat Buchanan, the lesson is clear. Uncontrolled migration brought down the Roman Empire, and the modern West—having now seen its share of world GDP drop by a quarter from a peak of 80% at the turn of the latest millennium—needs to reassert both control of its borders and belief in its values to arrest further decline. As tempting as this type of equation might initially seem, a more considered look at the role of migration in Roman system collapse has an entirely different message for the modern West.

A simple equation of the role of migration in Rome’s unraveling and the travails of the modern West is laboring under a basic misapprehension. Rome’s was an overwhelmingly agricultural, essentially steady state economy. There was no way to increase GDP in anything but the very long term, since tractors hadn’t been invented, and the stock of good agricultural land was pretty much fixed. As a direct result, any political struggle for the control of wealth—essentially for land, the source of the vast majority of it—was bound to generate winners and losers.  More good quality land could not just be magicked into existence, and the establishment of the successor states across the fifth century naturally saw partial or sometimes (as, it seems, in Britain) total confiscations of agricultural assets from their existing owners to the followers of the immigrant dynasts.  

Modern western economies, however, are neither steady state, nor agricultural. They grow, and, as a result, the enrichment of a new population element does not have to come at the direct expense of the existing population. More than that, the economic data is categorical.  While particular sections of an indigenous workforce may lose out, immigrants are straightforwardly good for a host economy as a whole and will punch above their weight in terms of GDP. One mainstream IMF study indicates that, on average, each 1% increase in the number of immigrants will add 2% to GDP. If, in addition, you add in some important longer-term demographic trends, there is a pressing reason why the vast majority of western economies have not just benefitted from flows of migration, but are actually dependent upon them, and will inevitably become more so in the very near future. 

As late as the 1800s, nearly 50% of German children did not make it to adulthood, and the situation was little better in other parts of Europe. Then, mid-century, improvements in sanitation, nutrition, and inoculation suddenly enabled European children to survive in unprecedented numbers. In consequence, the last few decades of the nineteenth century—at the height of the colonial era—saw Europe’s share of total world population rise from its long-term average of about 15% to a staggering 25%. European populations were breeding like rabbits and spreading over the globe in vast numbers.  

Eventually, however, the realization that pretty much every child was now going to make it to adulthood combined with unprecedented prosperity (meaning, amongst other things, that parents were no longer economically reliant on their children in old age) to undermine the imperative for large families. Over the course of the twentieth century and beyond, average family sizes have steadily reduced right across the developed world. Currently, only women in Iceland and Israel are having the canonically average 2.1 children each, which is required for an existing population to reproduce itself in the next generation.  Everywhere else, birthrates are well below this level and in some cases—particularly Germany, Hungary, and Japan—far below. At the same time, in a development which has so far partly masked the longer-term effects of falling birth rates when it comes to total population sizes, medical advances have greatly extended average lifetimes. Since 1945, the average male lifespan in the UK has increased by twenty or more years, with similar (sometimes even larger) increases right across the developed world.  

This is of course wonderful news. As a 63-year-old British male, I’m very happy to think that my average lifespan has an extra 17 years in it compared to what faced my grandfather at the same age. Combined with the simultaneous fall in birthrate, however, it has created a demographic-cum-economic timebomb, whose detonation threatens to explode what remains of western prosperity. Taken together, the two have massively increased dependency ratios, the balance between those working and those who have passed on into retirement.  

Which brings the importance of immigration for pretty much every country of the developed West firmly into focus. Not only do immigrants add to national GDP, but, crucially, a steady flow of migration is becoming absolutely critical to rectify the ever-increasing imbalance in indigenous western labor forces created by the confluence of falling birthrates and increasing longevity, especially when the latter generally also comes at the cost of spiraling levels of expensive health care later in life.  

This is an inescapable and straightforward reality, even if western public discourse around the subject of immigration is largely refusing to acknowledge it. Hidden in small print of the latest budget from a Conservative government—still rhetorically committed to UKIP-like hostility toward immigration—is an acknowledgement that 250,000 immigrants a year will be necessary to sustain even a low level of economic growth over the lifetime of the current parliament. And this, arguably, is actually not enough. Canada, for instance, repairs the similar imbalances in its dependency ratio by recruiting immigrants annually to the level of 1% of its existing labor force (i.e. 325,000 per year: an equivalent figure for Britain would be 650,000).  

These new realities urgently need to become a core element in western discussions about immigration. The other underlying reality, which is only just beginning to win any kind of general recognition, is that the same demographic transition to much smaller families that unfolded across the developed world in the twentieth century is already affecting the rest of the planet. Current estimates suggest that within two decades, western countries will have to be positively recruiting immigrants from a rapidly decreasing pool of potential candidates to fill widening gaps in their labor forces. At that point, those countries like Canada, which respond positively to the new realities of global demography sooner rather than later, are likely to enjoy a considerable recruitment advantage.

One part of the message that emerges from any comparison with Rome, then, is very simple.  Modern immigration into the developed world is totally unlike the kind of immigration which played its part in the unraveling of the Roman west. It doesn’t threaten western prosperity but is actually playing an increasingly important role in supporting it, in an era of declining birthrates, greater longevity, and increasingly problematic dependency ratios. If, however, we expand our discussion of migration in the modern world, to include its other, non-western dimensions, then the Roman comparison offers another, potentially still more important lesson.

In reality, the current furor about immigration in western public discourse is missing the most important modern migration story of them all. It fails to notice that many times more people have been on the move across the developing world itself. Beginning in the old colonial era, countless millions have relocated particularly to coastal cities like Shenzhen, São Paolo, Lagos, Mumbai, and many others. In numerical terms, this is the largest migration process in the entirety of human history. It also created the huge labor reserves, which have caused so much of actual industrial production to shift away from the developed world in the last few decades as so-called globalization unfolded. The process is non-reversible and not at all complete. Public attention focuses on the growing wealth of China, but that is yesterday’s news. At a moment when Sudan has fallen into chaos, it is worth emphasizing that seven out of ten of the world’s fastest growing economies are currently located on the continent of Africa.

It is in thinking more about this process—astonishing levels of economic development in different parts of what used to be the periphery of the western world’s global empires—that bringing Rome back into the picture can help explain exactly what’s going on. Comparing the overall development of the Roman imperial system with that of the modern West, an underlying pattern emerges. Over the long-term, the functioning of imperial systems generates limits and brakes on that system’s continued functioning: creating, in effect, an overarching imperial lifecycle. Imperial systems come into existence to enrich certain elements at the imperial core, but over the longer-term, they also kick-start revolutionary processes of economic and political change around their fringes, which eventually produce new entities capable of challenging the dominance of the original imperial core. The ancient Roman west was carved up by immigrant groupings whose size and coherence were the direct result of four centuries of transformative coexistence with Roman imperial power. The global dominance of the modern west is being challenged by the rise of new powers — such as China and India, but many others besides — whose economic development was originally kick-started to further the wealth of western imperial powers.

In the case of Rome, the outcome was always likely to be imperial dismemberment, because the rise of new powers within the Empire’s broader orbit was more or less bound to end in a struggle for control of a limited stock of good agricultural assets. The outcome in the modern world need not be so catastrophic. So far at least, the developing periphery is showing not the slightest need or desire to invade the old imperial core. There are complex problems to manage—not least pollution and climate change—but the stock of wealth-generating assets is not so limited, and there can potentially be enough economic growth to satisfy everyone else’s legitimate demands for a reasonable share of global GDP, while preserving plenty of wealth for the west. But this does depend on what choices are made by western politicians and the electorates that put them in power. If the demographic time bomb facing the west continues to be ignored, and immigrants demonized, then dependency ratios will increase to levels that must generate not just relative but absolute economic decline. The tectonic plates of the world economy have shifted in fundamental ways. Britannia no longer rules the waves, and you can’t even make America great again in the way this was true in 1945. Policies that attempt to turn the clock back and ignore the realities of the present will be deeply counterproductive. The most productive path to future prosperity lies in recognizing and making the best of new realities, not pretending that they don’t exist—however comforting that might be in the short term to some sections of western public opinion. 

Peter Heather is Chair of Medieval History at King’s College, London. His books include The Fall of the Roman EmpireEmpires and BarbariansThe Restoration of RomeRome Resurgent, and Christendom: The Triumph of a Religion, AD 300–1300. He lives in Oxford, UK. 

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