Kyle Harper’s The Fate of Rome contrives to be both an irresistibly good read—open at random and you will keep reading till supper—and a major contribution to the history of the Roman Empire. It's a very high standard to meet, considering that the serious study of history as such started with the 19th-century German historians of the Roman Empire.Setting aside the tales of writers ancient or modern, they were the first to line up the hard evidence of documents, inscriptions, coins, archaeology, to tell their story by stepping from fact to fact, frankly recognizing the gaps, and never ever weaseling past ignorance with “must have beens.” Instead of shrinking historical writing, the new rule triggered a hunt for evidence that was spectacularly successful: As one example, when inscriptions collected all over the empire by enthusiastic students were carefully correlated, the careers of individual imperial soldiers and officials emerged step by step, finally allowing us to understand why the Roman Empire was so uniquely successful for so long—outliving 10 Chinese dynasties. Imperial officers recruited natural talents everywhere, each recruit for the army or the bureaucracy was trained individually to set standards (Israeli basic training tironut is from the Latin for recruit), and then rotated around the empire from Syria to Yorkshire, from Tangier to Vienna, to learn how to fight and rule different cultures as the world’s first cosmopolitans. Retirees received decent pensions to raise families whose sons might be recruited in turn.Only the Jews rejected the bounties of this intelligent imperial rule, as documented in that most reliable of historical sources, Monty Python’s Life of Brian: The Jewish rebel played by the irresistibly funny John Cleese bitterly complains “They’ve bled us white, the bastards. They’ve taken everything we had ... and what have they ever given us in return?” Another insurgent blurts out: “the aqueduct.” Then another: “sanitation ... you remember what the city used to be like ...” A third voice adds: “And the roads ...” The rebel replies, “All right, well yes obviously the roads. ... But apart from the aqueduct, the sanitation, and the roads ... what have they ever done for us?” At that point others add: “Medicine ... Education ... Health ... Public baths!” But then the Cleese character ends it: “All right ... all right ... but apart from better sanitation and medicine and education and irrigation and public health and roads and a freshwater system and baths and public order ... what have the Romans ever done for us?”Kyle Harper shows that the ungrateful Jewish rebel was right all along: Carefully citing skeletal studies of burials dug up in England, he proves that under Roman rule people became shorter and sicker, because all the benefits of clean water and baths were outweighed by the unprecedented growth of cities, in which there was no escaping from the bacterial and viral infections brought from the eastern provinces over well-built roads and pirate-free sea crossings—the old life of rude hamlets cut off from the world had been much healthier, and people duly became taller and healthier again once the empire collapsed.That is what The Fate of Rome offers, the summoning of all the scientific evidence newly available to illuminate the Roman past, including the inconvenient truth of ice cores and tree rings (yep, there was a very warm age of great crops before Al Gore) and what makes it all work as both excellent reading and excellent history is that Harper skips across different provinces, different centuries, and different kinds of scientific evidence not just to keep us amused with colorful details, but to allow us to see the Roman Empire in a completely different way.In this book, bacteria and virus (yep, fourth declension: not viri) are restored to their proper station in life: not down in the dirt, but alongside emperors, senators, imperial legates, sometimes to help them by killing off previously unexposed barbarians, and more often to kill them with slow homegrown pneumonias or sudden violent fevers. After reading Harper, few will credit the frequent accusations of palace poisonings, most famously against Livia, wife of Augustus: All his descendants sickened and died, clearing the way for Tiberius, Livia’s son by her previous marriage. But the poisoner was probably the toxin of Vibrio cholerae bacteria that prosper in the raw shellfish that Romans still consume enthusiastically—the Jewish Prince Herod Agrippa who was raised by Augustus with his own grandchildren was the only survivor: He ate no pork, or shellfish.I particularly appreciate the achievement of this book because I myself once ventured into medical history to reevaluate Justinian’s low standing as a strategist, and found it hard going. That is a black mark for a man whose unique talents in all other ways no historian can deny—and one was a unique ability to recruit hidden talents.He married an actress raised as a prostitute and instead of a brief, scandalous, marriage in Theodora he acquired a stalwart, highly effective co-ruler, something never seen before, and affirmed till this day by their exactly matched images in the splendid Ravenna mosaics.He entrusted the design of his hugely ambitious Hagia Sophia megachurch with its giant floating dome to a pair of mathematicians who had never built anything, and it still shames all the other buildings of Istanbul, while copies can be seen in hundreds of cities on all continents.He chose the bureaucrat Tribonian to straighten up accumulated Roman laws and ended up with the Corpus Juris Civilis, the basis of Western legal education and now global law—the first universities were started to teach that one massive work; and when it came to generals, his pick was Belisarius, very likely the most admired general in history whose brilliant feats have been studied and copied ever since.Yet when I started writing my Grand Strategy of the Byzantine Empire, all the standard works declared Justinian a failed strategist, guilty of error No. 1: pursuing early victories in North Africa and southern Italy far beyond their culminating point in his attempt to recover the Western Empire, thereby weakening the Eastern Empire he already had.All along there was the evidence of the great historian Prokopios that everything was going very well indeed for Justinian until 541, when a great pestilence suddenly arrived “by which the whole human race came near to being annihilated.” In page after page, Prokopios described in full detail the disease, its symptoms, and its effects on individuals, on different cities and provinces, on city dwellers, peasants officials and—crucially—on the soldiers living and then dying in their forts, castles, and bases. Of the capital he wrote: “at first the deaths were a little more than the normal, then the mortality rose higher, and afterwards [the number of dead] reached five thousand each day, and even came to ten thousand, and still more than that.”So there was no overextension: Prokopios explains that Justinian’s very successful reconquest was abruptly interrupted by calamitous disease—not his fault. But this evidence was ignored by modern historians, because of the corrupting influence of “structuralist” literary theory, according to which everything written is made up to promote some hidden agenda.Prokopios was accused of wildly exaggerating some passing seasonal fever for the only purpose of copying the ultimate historian Thucydides and his deservedly famous account of the plague in Athens of a thousand years before.I was sure this was utter rubbish, especially after reading the Greek and Syriac chroniclers with no literary ambitions who also described unprecedented mass deaths.But lacking Harper’s easy familiarity with the scientific literature, it took me forever to uncover the DNA evidence that Justinian’s pandemic was caused by an exceptionally virulent biovar of Yersinia pestis, the bubonic plague—entirely different from any known plague till then and uniquely lethal. Like our own COVID-19, its much later return as the “Black Death” started in China to reach Europe from 1347, killing between a quarter and a half of the population. But when it had first arrived in Justinian’s time from 541, it was an entirely new pathogen, there was no acquired immunity at all, and Yersinia pestis could therefore kill as many as half of the infected, which was practically everybody but for hermits in the desert.When I looked for confirmation in other evidence, I too, like Harper—but again without his expertise—turned to ice-core studies. What they showed would evoke lots of enthusiasm these days: sharply declining carbon dioxide levels from 541. The only possible explanation is that mass deaths caused the reversion of farmed fields to natural greenery and then CO2 absorbing forests, while the abandoned cattle that might have kept down the vegetation was instead eaten by the wolves, bears , lions, cheetahs, and Caspian tigers that multiplied once humans waned.Justinian survived the bubonic plague and so did his empire but in much weaker form—it did not really recover from Yersinia pestis until 300 years later, and by then Arab raiders from the salubrious desert had penetrated into much of the ancient world with their new religion. As is true even today with our own virus, when the plague arrives it strikes city dwellers much harder than the truly rural, for whom “social distancing” is not a learned skill.It has somehow become normal for metropolitan Americans, including very rich ones, to live just like Roman proletarians: not in houses with a garden or in mansions with a planted courtyard but in apartment houses, in cubes and rectangles placed on top of one another. There were no hedge funds, mutual funds, or bonds in the Roman world, so the only way of converting a lump sum—such as a senior officer’s share of the loot of a conquered city—into a steady income was to invest the looted gold and silver, or the sale value of the captured slaves in the construction of one or more apartment houses as rental properties known as insulae. Their height was only limited by the maximum water supply level of the nearest aqueduct—Roman rental housing did have toilets—so they might go up higher than the four-floor standard, in which the top floor had to have low ceilings to allow the street level shops or taverns to have high ones.Nobody who invested in an insula would dream of living in one: They were for the working poor who made just enough to eat, drink, and pay rent, and who had to tolerate the steep stairs, narrow corridors, and the noise. Anybody who could lived in a house because even a small one off a narrow alley offered its portion of private space between Earth and heaven. Moreover, when a deadly summer fever or winter pneumonia arrived, mortality was much lower than in crowded apartment houses.I confess that personally I have never understood how people can live inside apartments without immediate access to outdoor greenery, and with every square foot accounted for, especially in Manhattan where I found even the ample penthouse terrace of a friend unbearable, because of the unceasingly fierce roar of the city.So I am really not the right person to ask the obvious post-coronavirus question: How many years of tiresome commuting are justified by each month of antiviral lockdown? None, of course, if it will never happen again, but that can only be so if the next virus is unresisted and allowed its portion of flesh, not kept in check as our COVID-19, which is therefore free to return.