Blame the gerbils

The notion​ that human history is determined at bottom by natural forces and non-human factors seems to be an idea whose time has come. In Prisoners of Geography (2015), Tim Marshall argued that the fate of nations depends on their rivers and mountains, frontiers and coastlines. In The Earth Transformed (2023), Peter Frankopan added climate to the list: drought in Central Asia caused the fall of empires in Europe, and the Little Ice Age did the same for the Ming dynasty in China. Jonathan Kennedy’s Pathogenesis: How Germs Made History (2023) studied plagues and their effects from the Stone Age to the present: it was a plague pandemic around 3000 BCE that cleared the way for the incursion into Europe of the Western Steppe Herders, speaking the Indo-European languages that were the basis for almost all those of modern Europe.

One attraction of such theories is that they are not local or even regional, but truly global; another (especially with Frankopan’s) is that they may contain a warning for our own time. Yet as James Belich writes, ‘historians are extremely uncomfortable with the idea that natural forces in some way circumscribe human agency.’ In The World the Plague Made he has a hard case to make, and a somewhat heartless one: that the Black Death – perhaps ‘the most lethal catastrophe in human history’ – had a silver lining.

The history of plague has been much debated in recent years, though some things at least are settled. The pathogen of bubonic plague is the bacterium Yersinia pestis, whose DNA has been recovered from human remains, and whose variations have been traced. Surprisingly, ‘all highly virulent Y. pestis strains had their origin in the Tien Shan mountains,’ in modern Kyrgyzstan, where the host has always been the grey marmot, a large rodent. There have been three known pandemics: the Plague of Justinian, beginning in 541 CE; the Black Death, beginning in 1345 and persisting with recurrent outbreaks for more than three centuries; and finally the much smaller pandemic that broke out in south-east China in 1894 and ran for some thirty years. The Black Death was therefore a rare event, ‘with only one generally accepted precursor and no equivalent successor’.

Belich has revisions to make to the traditional account. One concerns the mortality rate. The standard estimate has been about 30 per cent of the population of Western Europe in the first strike (1346-53), which many have thought must be too high. New evidence suggests it was more like 50 per cent, and the difference was important for the survivors. If harvests went down 40 per cent, and the population loss were only 30 per cent, then it would have meant dearth for the survivors. If the dieback was 50 per cent, however, the survivors had ‘modest abundance’.

The next revision concerns recovery rate. This was once thought to be relatively rapid, taking perhaps a century, but that now seems another underestimate. England did not return to its pre-plague population until about 1625, 280 years after the first strike. During most of that period Western Europe had about half the population it had in 1345. And yet 1400-1500 ‘is the very century in which Western Europe’s global expansion began’, the period of what has been called ‘the Great Divergence’ between Europe and the rest of the world. ‘The Black Death and the Rise of Europe’, as Belich’s subtitle has it, do seem to be linked in time, and it may not be a coincidence.

There are still some questions to answer. First, how did the bacterium travel from the Tien Shan mountains to both southern China and Western Europe? In Europe the finger of transmission has long been pointed at fleas, rats and travel by sea. But Tien Shan is about the most landlocked place on earth, so some other mechanism has to be found. Marmots, unlike rats, are quite large creatures, not easy to be carried accidentally, and if their fleas were the problem, perhaps carried on marmot skins, how would they have survived long journeys without a host?

Belich’s answer inculpates the humble gerbil. Gerbils live in great warrens on the steppe, and overlap enough with marmots to catch the bacterium from them. A gerbil can’t travel from Kyrgyzstan to Europe any more than a marmot can, but a resting caravan of camels, near or even on a gerbil warren, might give an opportunity for fleas to jump to a new host. The fleas would then travel with the caravan until it reached its destination, probably on the middle Volga.

Transmission by hitchhiker, in other words, and demanding a rather unlikely combination of circumstances. That, Belich argues, is why it happened so rarely. Having arrived on the Volga, the fleas – which had skipped from marmot to gerbil to camel – would now infest the traditional European culprit, the rat. But not our kind of rat. We are familiar with the brown rat, Rattus norvegicus. Like the grey squirrel, it is an invasive species, which has taken over from (and eliminated) its predecessor, Rattus rattus, the black rat – otherwise known as the ship rat, house rat or roof rat. Smaller and less aggressive than their brown cousins, black rats appear to have been commensal with humans for many centuries.

But the big question remains: what connection can there be between the terrible death toll and Europe’s great expansion? Plagues are different from other catastrophes. Fire, flood and war destroy property as well as people. Famine makes people eat their seed corn and their animals. Plague does none of these things. If it halves the population then it doubles the amount of capital available per head. Or maybe more. In a rather Micawberish calculation, Belich points out that if a peasant’s annual income was £10 a year, and his subsistence costs £9, then his disposable income was only £1: a figure that would be doubled by even a 10 per cent increase in total income. This may have been a fairly common situation, since the main source of capital in the medieval world was land for food production, and vacated land would naturally be taken up by anyone still alive to make use of it. Despite the collapse in population, the English government was still collecting 95 per cent of its pre-plague tax revenues between 1352 and 1354. Huge numbers of people had gone, but the underlying economy of land and food wasn’t much affected. The increase in disposable income for the fortunate boosted ‘luxury’ trades: spices, clothing, the ‘new draperies’ from India and China, and eventually tea and sugar.

Increased prosperity would have had further knock-on effects. There would have been more land per head, but less labour per acre. This provoked ‘a sharply increased uptake of three existing inanimate sources of energy: water power, wind power and gunpowder’ – water wheels for fulling and mining, windmills for milling and draining, and more advanced weapons. All this led to reduced prices for commodities such as iron, paper and cloth. With fewer people to man ships, labour-intensive galleys gave way to sail. Galleys, however, were able to mount one or two heavy guns, an advantage that had to be redressed by redesigning sailing ships so they could mount cannon lower down. This arms race led to the development of the ‘gun-galleon’, a major factor in the ‘rise of Europe’.

Breakthroughs like this, Belich argues, wouldn’t have happened without the ‘traumatic pressure-cooking’ of the plague. Another result of the trauma was the creation of ‘crew culture’. Labour shortage led to a shift from ‘corn to horn’, i.e. from arable to pastoral farming, since herding sheep requires far less labour than ploughing the land – as Thomas More pointed out in Utopia, 170 years after the Black Death. Now, freed from the harvest bottleneck, relatively large numbers of men became available to sign on as full-time soldiers or sailors. Or, for that matter, as cod-fishers, whalers, fur-trappers or loggers, all operating in crews or gangs. These men were ‘the cutting-edge of European expansion, as disposable as razor blades’. Labour shortage had, counterintuitively, created a labour surplus, which soon found new and profitable employment.

Another unexpected knock-on effect was seen in Genoa. The city’s population, like England’s, had been halved by the plague, and in 1350 was faced by war, which required a ‘huge financial as well as military effort’. This was met by selling shares in the public debt, tradeable and interest-bearing. With their ‘plague-boosted disposable incomes’ the citizens of Genoa responded eagerly to the investment opportunity: by one calculation, they supplied 108 tons of silver in total. It’s hard to know exactly how much effect this initiative had on the growth of financial institutions throughout Europe – central banks, joint stock companies, tradeable public debt – but Belich suggests that capitalism unquestionably had its roots in post-plague northern Italy.

All this, Belich says, marks the ‘Great Divergence’, when Europe ceased to be an outlier on the Eurasian continent and began to gain political and technological dominance. He dates the plague era from 1350 to 1800, and divides that into two halves: until about 1500, plague ‘played few favourites’; it killed all classes, urban and rural alike. After 1500 it became more likely to strike urban dwellers, and the poor more than the rich. Outbreaks continued here and there (Messina in Sicily in 1743), and it remained a ‘lurking nightmare’ in popular consciousness for even longer – who knew if it had really gone away – but it no longer affected the continent’s demography after about 1710. What remains to be explained is the ‘Little Divergence’, when – after 1665, its last big plague strike – Britain rose steadily to global maritime hegemony and the Industrial Revolution began. Connecting this 18th-century rise with the plague era four centuries before, is, as Belich says, ‘to draw a very long bow indeed’. Still, while he doesn’t suggest that plague was the sole cause of this ascendancy, he claims that it is ‘the biggest under-recognised cause’.

One factor was the rise of rich peasants, expanding their holdings of vacated land and creating a new class of yeomen, and eventually a non-noble country gentry. ‘Crew culture’ was reflected in increased levels of shipping tonnage, making English sea power a major force by about 1500. London regained its pre-plague population later than the rest of the country, but sharply increased its share of the national wealth. By 1700 London dominated overseas trade so much that it handled 80 per cent of all exports to Africa and the Americas, with profits available for re-investment. Other areas played their part in industrialisation, ‘but it was the London magnifying glass that concentrated plagued and global rays on these hearths until they burst into industrial flame.’

Implicit in Belich’s subtitle is the idea that only Europe received the unexpected boost that came with the halving of its population. Belich thinks that although similar effects were felt in the Muslim world they have been disguised for us by our limited understanding of ‘empire’. To Europeans, for obvious reasons, ‘empires’ consist of a homeland plus its colonies and acquisitions: these are overseas empires, fragmented. But they are only a subset of the imperial institution. Belich makes the point by contrasting, or equating, two 16th-century events. One was the overthrow by Hernán Cortés and his conquistadores of the Aztec empire in 1521, using the full ‘European expansion kit’ – ships, crews, horses and guns. The other was in 1590, when another ‘small army of musket-armed conquistadors set out to invade a distant, gold-rich empire, and reached it after a five-week journey’. Events then followed the familiar pattern: guns beat numbers, the invaded emperor was taken prisoner under pretence of peace talks and killed, a puppet relative installed in his place and rebellion ‘bloodily suppressed’. But this was not Cortés again, or even another European initiative. It was a Moroccan invasion of Songhay, in West Africa, and ‘the 1700-kilometre space between metropolis and colony consisted of Saharan sands, not Atlantic water.’

The ‘European expansion kit’, then, was readily copied outside Europe, with the exception of sea power. Belich notes the creation of ‘contiguous empires’, where the acquisitions and the homelands weren’t physically separated at all: the Russian takeover of Siberia and (not usually regarded as ‘imperial’, though one has to ask why not) the American expansion across a whole continent, with an even more dramatic suppression of the Indigenous inhabitants. All these developments, he argues, along with several others, like the creation of the Ottoman and Mughal empires, stemmed at bottom from the creation of ‘plague-forged expansion kits’.

So, in general, events on the global scale happened much as they did on the local scale: there were few survivors, but those who did survive became richer and more powerful. And none of it would have happened without the unexpected stimulus of a sudden relief from the Malthusian pressure that was part of the nature of the premodern world: population constantly increasing, but not matched by production of food. That is the thesis of this data-crammed volume, but its global scope involves considering some apparent anomalies. One is ‘the Dutch puzzle’: how did Holland come to punch so much above its weight in the era of expansion? A factor in Holland’s successful fight for independence was the pirate fleet of ‘Sea Beggars’, said to be staunch Calvinists but with a dreadful reputation for brutality and plunder: ‘this looks more like plague-incubated crew culture than Protestant piety.’

Another puzzle is the ‘entanglement’ of Genoa with Spain and Portugal, well represented by Christopher Columbus. Belich argues that the Iberian peninsula got the same plague boost as the rest of Europe and developed its own ‘expansion kit under the pressure of more capital, more war and less manpower’. Genoa, meanwhile, ‘led Europe in expansive techniques in the early plague era’, looked west rather than east, and ‘played midwife’ to the global expansions of both Portugal and Spain. Without all this the world would be a very different place.

These are only two of many chapters on particular areas: China, Russia, the Ottomans, the Mughals and others. All of them are informative and often provocative – not least the last chapter, ‘Plaguing Britain’, which takes on many controversial issues, including the profitability (or otherwise) of slavery, the ‘transposition’ of the cotton industry from Bengal to Lancashire and even the ‘huge rise in illegitimacy’ during the 18th century, ‘a characteristic of crew culture’, as Britain became in some respects a ‘crew country’. (Perhaps it still is.)

Belich concludes by saying that his case isn’t that plague was ‘the dominant piece, the master variable, in the three-dimensional jigsaw of global history after 1350’. What he does claim is that it was ‘the biggest missing piece’, generally underplayed, regarded as tragic but ephemeral. In fact, its effect was revolutionary: after all, ‘if the sudden halving of people and the doubling of everything else is not potentially revolutionary, what is?’