William Rosen


Errata (with apologies)


(appearing only in the first hardcover printing)

Page 1, line 3

"...proportional to the bodies' mass, and inversely proportional to the length of a straight line..." should have read "...proportional to the centers of the bodies' mass, and inversely proportional to the square of the length of a straight line..."

Page 4, 2nd line from bottom:

A missing endnote after the word “superstate”; this endnote should have read, “Daniel A. Foss, ‘Third and Sixth Centuries East and West’ online article, www.hartford-wp.com/​archives/​55/​046.html

Page 4, line 9

"74 C.E." should have read "31 B.C.E."

Page 25, line 5

“…two more corulers: Galerius and Constantius, with the former based in the Rhineland city of Trier, and the latter in Sirmium…”should be “…two more coruler: Contantius and Galerius, with the former based in the Rhineland city of Trier, and the latter in Sirmium…” [thanks to Richard Juhnke]

Page 51

The footnote that now reads “...Tarraconensis, Baetica (most of modern Portugal), and Lusitania in the south.” should have read “...Tarraconensis, Lusitania (most of modern Portugal), and Baetica in the south.”

Page 101, line 9

"Walter Gropius" should read "Louis Sullivan" (thanks to Dr. John Reinus for pointing this out)

Page 137, line 3

"artistocrats" should read "aristocrats"

Page 173, line 20

"another" should have read "other"

Page 183, line 30

"dense" should have read "denser"

Page 184, line 2

"in the range of 3 x 10 inches" should have read “in the range of 10 to the 11th power” (Note: the proofreader undoubtedly saw 11 as the superscript, and confused it with the sign for inches: " )

Page 185, line 12

"...inland, was R. rattus..." should have read "...inland, it was R. rattus..."

Page 194

Not really a correction, but an update. In the section of the book in which the origins of Y. pestis are debated, I compared three regions that seemed likely candidates: China, India, and East Africa. Based on what seemed the best arguments available in 2007, when the book was published, I supported the African genesis. However, in October of 2010, a group of medical geneticists, led by Stephanie Haensch at Johannes Gutenburg University and Barbara Bramanti at Institut Pasteur, published a paper that strongly suggests a Chinese origin -- not merely for the biovar that caused the Justinianic Plague, but also the Black Death of the 14th century. (It also casts a lot of doubt over the existence of the so-called "Antiqua" biovar of the bacterium...but it also confirms beyond any doubt that Y. pestis was indeed the pathogen responsible for the pandemic, though it hasn't shut up some of the doubters who still believe it was a combination of typhus and hemorrhagic fever.)

Page 213, Line 3

“…seventh-century physician Isidore of Seville...” should have read, “… seventh-century bishop St. Isidore of Seville...”

Page 223, footnote

"...from the Book of Jeremiah, 19:21" should have read "...from the Book of Revelation, 14:19"

Page 320, line 11

"...1458..." should read "...1453..."

Page 322, line 24

"...528..." should read "...628..."

Page 354, index entry

“Chrysotom, John" should have read "Chrysostom, John"

JUSTINIAN'S FLEA: The First Great Plague and the End of the Roman Empire

An excerpt from Chapter Nine


This disease always took its start from the coast, and then went up to the interior.”
Procopius, History of the Wars, II, xxii, 8


It began, as it always began, at the docks. From there, it climbed inexorably, week after week, a rising tide visiting the judgment of God on His people. Though Procopius could not, of course, know this, the plague was borne not by miasmic air (or by the supernatural creatures that he reported some victims saw before becoming ill) but by the rats that carried their fleas into every neighborhood. The geography of the city conspired with them; one reason that the Emperor Constantine was inspired to name his capital New Rome was that, like the original model, it had seven hills. The base of each one was stricken by the demon first, giving those who lived on the hilltops the same useless warning as the occupants of the top deck of a sinking ship.

In retrospect, the demon’s targets had all the evidence required to identify its carriers. They knew, as modern zoologists know, that rats are never found more than a few hundred yards from a human habitation. And they knew that the plague, like the rats, always spread outward from the harbors and the granaries.

The best evidence is that the peak of the first wave of the epidemic lasted only four months, after which both rat and human populations had crashed so fast that Y. pestis could no longer spread. But for one hundred days, Constantinople was a window onto Hell. Every day, one, two, sometimes five thousand of the city’s residents – one in one hundred of the pre-Plague population – would become infected. A day’s moderate fever would be followed by a week of delirium. Buboes would appear under the arms, in the groin, behind the ears, and grow to the size of melons. Edemas – of blood – infiltrated the nerve endings of the swollen lymphatic glands, causing massive pain. Sometimes the buboes would burst in a shower of the foul-smelling leukocytes called pus. Sometimes the plague would become what a modern epidemiologist would describe as “septicemic” ; those victims would die vomiting blood from internal hemorrhages that formed even more rapidly than the buboes. Those who contracted septicemic plague might have been the fortunate ones; though they all died (bubonic plague kills “only” four to seven out of ten victims, septicemic plague is virtually 100% deadly) they at least died fast. They weren’t tortured with pain for a week or more, nor did they go insane, as thousands of citizens of Constantinople did, leaping into the sea in the hope of ending their suffering.

As a dying body becomes incapable of replacing deoxygenated with oxygenated blood, the muscles surrounding the human voice box become more acid. They go into spasm, and make a characteristic dry, shaking sound. The normal hum of life in Constantine’s city had been overtaken by the sound of a thousand death rattles a day.

* * *


If the first line of defense for a single organism facing attack from the bacterium was the Innate immune system, society’s first responders, then and now, were the city’s doctors.

By Justinian’s day, the profession of medicine was as stratified as the Catholic Church. At the very highest rank were the empire’s court physicians, themselves almost always aristocrats – comites, or counts. Below them on the ladder were the empire’s public doctors, those who were paid by their respective cities for their services, among whom the highest ranking, dating from the early 5th century, were the public physicians of Rome (commanded by law to “honestly attend the poor, rather than basely …serve the rich.” ). Lowest in both status and income were the private practitioners of medicine.

Almost as important as a physician’s position was his educational credential. What Berytus/​Beirut was for lawyers, Alexandria was for physicians. There, a four-year course of study was offered by professional teachers of medicine – the iastrophists, who were not merely scholars but indispensable consultants for any complicated case. That the same city should be the port of embarkation for both disease and doctor has an element of irony.

The training that Constantinople’s physicians secured, whether in Alexandria or elsewhere, was largely an immersion in the work of the the 2nd century philosopher-physician Galen, the Mediterranean world’s dominant medical authority for more than a millennium. Galen’s humoral theory of disease was little help in coping with any infectious disease, much less one as virulent as plague, but his disciples were not without resource in caring for the sick. During the 6th century, the greatest physicians of the known world, including Aetius of Amida and Alexander of Tralles (brother of the great architect Anthemius) resided in Justinian’s empire, though not always in his capital (Alexander eventually settled in Rome). Alexander’s pharmacopoeia, and those of his contemporaries, were heavily weighted toward spells, folk remedies, and charms, including the use of gladiator’s blood to treat epilepsy. Cold water treatments had been a popular cure since the founding of the empire – Augustus, particularly, is said to have favored it – and one of the most famous physicians during the reign of Leo, Jacobus, earned his use-name “Psychristus” for his enthusiasm for the treatment as a sovereign remedy. Another clinical tactic much in demand was the treatment of disease by the application of material that had been blessed by a saint, preferably a hermit. These literal “blessings” or eulogia, were frequently no more than dust or red clay that had been touched by a holy ascetic. Others included magical amulets and rings (frequently carrying the image of the biblical King Solomon)

Cold water, saint’s relics, and magic amulets offered only the relief found in placebos, but – like placebos – they were also generally harmless. The same cannot be said of drugs that were known to the physicians of late antiquity, who spent much of their training in their use … though the training was not without its magical components. Galen’s drug categories were based on a mild sort of sympathetic magic; the 7th century physician Isidore of Seville described the theory behind it so: “every cure is brought about either by the use of contraries or by the use of similars. By contraries, [we mean that] a chilling disease is treated with heat or a dry one with moisture…” . But the contraries and similars were frequently powerful alkaloids like the atropine found in mandrake and belladonna, purgatives like copper oxyacetate (verdigris) or the “juice of the opium poppy” all of which were in wide use in 6th century Constantinople. The 7th century Alexandrian physician Paul of Aegina, in contrast, did far less damage, and probably an equal amount of good, with his belief that a homely substance like butter was useful for reducing the swelling caused by the plague’s distinctive buboes.

Clearly, the 6th century pharmacopoeia was of negligible use in treating plague (or in fact, most any infectious disease) though a modern reader must guard against a smugness about primitive medical practices. Physician and author Lewis Thomas, remembering his own medical education in the first half of the 20th century (Dr. Thomas graduated medical school in 1933, and practiced almost until his death sixty years later) writes movingly of the limited therapeutic lessons of the medicine of the day: A doctor’s job, in 1933, was to “diagnose, enlist the best possible nursing care, explain things to the patient and family, and stand by.” In this, he was far closer to the practice of medicine described by Alexander in his 12-volume Therapeutika than to that employed by the time of the Second World War. A modern physician appalled by the use of charms and folk remedies would nonetheless find Alexander’s approach to medicine familiar, particularly his respect for peira, the experience of a clinician willing to try anything that might alleviate the discomfort of his patients…even if sometimes that means using magic charms to treat pain for a patient unwilling to take medicine orally or rectally.

The limitations of the physicians of late antiquity would be shared by their successors well into the twentieth century, for until the discovery of broad-spectrum antibiotics the only weapons available to combat deadly infections were those of the body’s own immune system*. One in three victims – those with a combination of good fortune, strong underlying health, and an uncompromised immune system – survived an infection of bubonic plague during those horrific months. One of them was the emperor himself.

Justinian’s exposure and survival is evidence of both the egalitarian character of the disease’s vector, and the vigorous nature of his body’s defenses. The specific progress of Justinian’s illness is undocumented, but he seems to have escaped the worst of the uncontrollable inflammatory response caused by the disease’s endotoxins. As a result, though he spent weeks on the brink of death (during which time Theodora was effectively ruling the entire empire) and his demise was regularly rumored, he survived, both the disease, and the problematic ministrations of his physicians.

The tools available to those physicians attempting to treat the disease clinically were only slightly less effective than their ability to control its spread. Attempts to treat infectious disease by traditional public health tactics, including quarantine, were in wide use by the 6th century, though problematic in effect; When Bishop Nicholas of Sion banned farmers from entering his town on market days in order to limit the poorly-understood spread of the disease, he was nearly arrested by the municipal authorities who believed he was manufacturing a famine in order to drive up prices. More effective, because more widely available, was the one great medical innovation of late antiquity: the hospital, which evolved from the Christian xenodochia, combinations of treatment centers, hospices, and poorhouses, which spread from their original locations in Judaea during the late 4th Century; to Rome, Ephesus, and (largest of all) the hospitals built and staffed by St. John Chrysostom during his tenure as Bishop of Constantinople.

Justinian himself terminated the state subsidy paid directly to physicians and transferred them to the hospitals, which were by then functioning very like modern medical centers. The largest of them, St. Pantalaimon, had been built on the site of the house occupied by Theodora upon her return to Constantinople and modesty – the place where she spent her last days before meeting Justinian, famously, if legendarily, spinning wool,. But large as Constantinople’s hospitals were, they were overwhelmed within weeks by victims of the demon, for whom they could do little except house them until they were ready for burial.

* * *


On the first hill of the city, at the south end of the Bosporus where Constantinople’s peninsula curls like the bottom of a letter C, stands the Hippodrome, Hagia Sophia, and the Emperor’s palace. From that hill, Justinian and his ministers watched the destruction of their capital. A city the size of Constantinople has a “normal” death rate estimated at thirty a day. Increasing that by two orders of magnitude put a crushing burden on the business of easing the departed on their way to heaven. Fifty years later, Bishop Gregory of Tours would write about the pestilence,

“Since soon no coffins or biers were left, six and even more persons were buried together in the same grave. One Sunday, three hundred corpses were counted in Saint Peter’s basilica [in Clermont] alone.”

This was nothing compared to the problem facing Justinian. In very short order, the existing burial grounds were filled, then every square foot of new ground; gigantic new cemeteries were built across the Golden Horn at Sycae. At the same time, the population that was filling up the graves rapidly overtook the population that could dig them – those who were still healthy, and not spending every waking hour caring for victims. Though burial had always been a family responsibility, Justinian could not ignore the problem, and detailed a minister named Theodorus to find a solution. A Christian city could not contemplate cremation. Instead, Theodorus looked to the walls.

Eighty years after Constantine’s death, when Alaric’s Goths sacked Rome itself, the ministers of the eastern Emperor Theodosius began construction of an immense series of walls that would surround and protect the imperial city from a similar fate. The Walls of Theodosius ran roughly north to south guarding the eastern portion of the city’s peninsula from landward attack, were nowhere less than twenty, and more frequently thirty feet high. Every 180 feet, a square tower sixty feet high was built from which Constantinople’s bowmen could save the city from any barbarian attack. The cemeteries at Sycae were likewise surrounded by such towers, which evidently inspired Theodorus with another idea of salvation. At his direction, Justinian’s troops removed the tops of dozens of the towers, and filled them with the bodies of the dead. “As a result,” Procopius writes, “an evil stench pervaded the city and distressed the inhabitants still more, especially when the wind blew fresh from that quarter.”

The internment of the dead was practically the only occupation that drew the city’s population out into the streets, which were otherwise desolate; as a consequence, the ovens of the city’s bakeries remained unlit. Justinian had constructed dozens of granaries and cisterns as insurance against another Nika Riot, but without bakers to turn wheat and water into bread, his prudence went unrewarded. “Indeed, in a city which was simply abounding in all good things, starvation almost absolute was running riot…” In an epidemic with a direct path of contagion, the lack of human-to-human contact might have exhausted the demon in days. Human starvation, however, did nothing for the rats and fleas except provide them with a huge new source of food.

* * *


As with so many of the events of Justinian’s reign, the most vivid chronicle of the plague’s arrival is that of Procopius, whose greatest talent as a historian may have been the good fortune to be present at the most significant events of his time. This is not to diminish his other abilities, including devotion to accuracy and a clear prose style, consciously modeled on that of Thucydides (despite a pronounced taste for Homeric excess). Nor is it to grant him any sort of consistent impartiality, which is one virtue he failed to exhibit in either his sycophantic record of Justinian’s architectural achievements – On Buildings – or his extraordinarily splenetic catalog of the moral failings of emperor, empress and everyone else, the Anekdota, or The Secret History, which remains the source of most of the stories of Theodora’s salacious past, Antonina’s scandalous lovers, and Justinian’s supernatural wickedness.

In the eight volumes entitled The Wars, however, he approaches the level of his idol, Thucydides, earning a Gibbonesque encomium: “His facts are collected from the personal experience and free conversation of a soldier, a statesman, and a traveler; his style continually aspires, and often attains to the merit of strength and eloquence.” It is in The Wars that his account of the plague appears, beginning with the famous lines:

“During these times, there was a pestilence, by which the whole human race came near to being annihilated. Now in the case of all other scourges sent from heaven some explanation of a cause might be given by daring men, such as the many theories propounded by those who are clever in these matters, for they love to conjure up causes which are absolutely incomprehensible to man… But for this calamity, it is quite impossible either to express in words or to conceive in thought any explanation, except indeed to refer it to God.”

The description of the disease itself is a model of clinical description: Victims “had a sudden fever, [though] the body showed no change from its previous color, nor was it hot as might be expected, but of such a languid sort that neither the sick themselves nor a physician who touched them could afford any suspicion of danger…But on the same day in some cases, the next day in others, and in the rest not many days later, a bubonic swelling developed, and this took place not only in the groin, but also inside the armpits, and in some cases also beside the ears, and at different points on the thighs….There ensued with some a deep coma, with others a violent delirium…who suffered from insomnia and were victims of a distorted imagination. and in those cases where neither coma nor delirium came on, the bubonic swelling became mortified and the sufferer, no longer able to endure the pain, died.”

Compare this with an epidemiology textbook written fifteen centuries later:

“Onset is sudden with chills and rigors and rise of temperature to 102o or 103o …severe, splitting headache and often pain in the limbs, the back and the abdomen. He may curl away from the light, or, as the painful bubo develops, take up some attitude in bed that relieves the pressure on the painful swelling. He becomes confused, restless, irritable, or apathetic, his speech slurred as if drunken [Procopius: “the tongue did not remain unaffected…lisping or speaking incoherently and with difficulty”] he is unable to sleep, sometimes wild or maniacal. He may bleed into his skin, or internally into his stomach or intestine or from his kidney… Within a day or two he is prostrate with all the symptoms of shock. His temperature may come down and he appears better on the third day or so, but this is deceiving; he is worse the next day and dead soon after. Most patients died between the third and sixth day."

But all accounts of the plague are revealing. A lawyer-turned historian from the eastern shores of the Mediterranean, Evagrius Scholasticus, was only a boy in his native Syria when the plague arrived in Constantinople, but nonetheless produced a remarkable account of the demon’s spread during subsequent years, and speaks with the privileged position of one of its victims::

“[The plague] took its rise from Aethiopia, as is now reported, and made a circuit of the whole world in succession, leaving, as I suppose, no part of the human race unvisited by the disease. Some cities were so severely afflicted as to be altogether depopulated, though in other places the visitation was less violent. It neither commenced according to any fixed period, nor was the time of its cessation uniform; but it seized upon some places at the commencement of winter, others in the course of the spring, others during the summer, and in some cases, when the autumn was advanced…at the commencement of this calamity I was seized with what are termed buboes, while still a school-boy, and lost by its recurrence at different times several of my children, my wife, and many of my kin, as well of my domestic and country servants…”

Given the widespread devastation that he reports, to say nothing of the personal injury he suffered at the demon’s hands, one can only call Evagrius’ account remarkably sedate. Though orthodox in his Christianity, his faith’s taste for the apocalyptic perspective was still tempered by the restraint of its Hellenic forebears.

Not, however, everywhere. As early as the “plague” of 251-266, Bishop Cyprian of Carthage could cheer the disease decimating his city with a “Kill them all and let God sort them out” sermon: “How suitable, how necessary is this plague and pestilence…the just are called to refreshment, the unjust are carried off to torture.” By the time of the plague’s arrival in Constantinople and the eastern Mediterranean three hundred years later, one can read:

"In this last millennium, which is the seventh, during which the kingdom of the Persians will be extirpated, the Children of Ishmael will come out of the desert of Yathrib and all come and collect there at Gab ‘ot Ramta…While I beheld these four heads of punishments, Devastation and the Devastator, Destruction and the Destroyer, they cast lots over the land. The land of the Persians was given to Devastation for him to devastate it, sending its inhabitants to captivity, slaughter and devastation; Syria was given to the sword of Devastation, its inhabitants to captivity and to slaughter; Sicily was given to Destruction and the sword, and its inhabitants to captivity and to slaughter; the Roman empire was given to Devastation and its inhabitants to captivity and to slaughter…”

Perhaps the most revealing account of the plague is that of John of Ephesus, a Syrian-speaking member of a monastic order who was a professed Monophysite, and in consequence a frequent refugee from waves of persecution whenever orthodox leaders were in positions of authority in Constantinople. At other times, particularly during the ascendancy of Theodora whose favorite he was, he enjoyed very high status indeed, even rising to a bishopric at Ephesus in Asia Minor. By his own no doubt exaggerated accounting, he was personally responsible for baptizing more than 70,000 former pagans living on the Anatolian plateau, he has been not inaccurately described as “a writer whose zeal exceeds his elegance,”

His Ecclesiastical History, of which only fragments have survived, contains by far the longest, and most apocalyptic, of the contemporaneous account of the plague. Comparing John to Procopius is an object lesson in the relative importance of prophecy over fortune:

“Thus, over these things the prophet [In this case, the author of the Book of Lamentations] might weep and say, ‘Woe upon me not because of the destruction of the daughter of my people, but because of the desolation of the entire habitable earth of humanity, which has been corrupted by its sins; and because the world in its entirety has already been made desolate for some time and has become empty of its inhabitants.”

and the preemption of the natural by the supernatural

“When this plague was passing from one land to another, many people saw shapes of bronze boats and (figures) sitting in them resembling people with their heads cut off. Holding staves, also of bronze, they moved along on the sea and could be seen going whithersoever they headed. These figures were seen everywhere in a frightening fashion, especially at night. Like flashing bronze and like fire did they appear, black people without heads sitting in a glistening boat and traveling swiftly on the sea, so that this sight malmost caused the souls of the people who saw it to expire.”

John’s chronicle reads, to a modern, like an unlikely combination of clinical accuracy and apocalyptic imagery. To his contemporaries, however, the missionary’s willingness to describe suffering on its own terms, rather than as a way to salvation is a pure expression of Monophysitism. To John – to many Monophysites – the argument that no distinction could be made between the human and divine attributes of Jesus was more than just a bit of empty theologizing. It also demanded a respect for a pragmatic understanding of disease. The demon killed and disfigured, not as evidence of God’s displeasure, but because all of reality is embraced in the Monophysite world . Perhaps for that reason, one of the more distinctive tropes of John’s Chronicle is its strained attempt to discover a silver lining around the pestilential cloud:

“Although [the plague] was very frightening, grievous, and severe, it would not be right for us to call it not only a sign of threat and of wrath, but also a sign of grace and a call to repentance. For the scourge…by its silence sent as it were numerous messengers from one country to another, and from city to city and to very place, just as if somebody were to say, ‘Turn back and repent…for behold I am coming…

“As in the days of Noah, when that blessed man together with his family heard the message of the threat and of perdition, he grew afraid, and did not disregard it but took care to build the ark…So also in this time in like manner as did that blessed man, many people managed in a few days to build ships for themselves consisting of almsgiving, that these might transport them across that flood of flame.”

Whatever his perspective, John’s eye for the telling detail is very real, indeed: Once the plague arrived in Constantinople, “nobody,” he wrote, “would go out of doors without a tag upon which his name was written and which hung on his neck or his arm” …a means of identification in case he died suddenly. One can, perhaps, imagine the grotesquerie of a mass grave so full that the living needed to march on top of layers of the dead in order to press the corpses more efficiently into the available space. John wrote,

“How can anyone speak of or recount such a hideous sight, and who can watch this burial, even though his soul should remain in his body and not waste away from bitter lamentations over so much iniquity which would suffice to destroy the children of Adam? How and with what utterances, with what hymns, with what funeral laments and groanings should somebody mourn who has survived and witnessed this ‘wine-press of the fury of the wrath of God?’”

Reviews for Justinian's Flea


"This is a remarkable book; the polymath author expatiates on subjects as varied as architecture, theology, jurisprudence, the art of war, and, of course, biology, as well as happily imparting the juiciest bits of imperial gossip. Part III, Bacterium, begins with a detailed account of the nature of the plague, traces its terrible spread across ancient Europe, and provides visceral descriptions of the ravaged Constantinople, 5000 citizens dying every day. The end of the world, thanks to a flea."
Talha Burki in The Lancet

"This is a very engaging, lively, and entertaining text that presents the story of the plague almost as a mystery tour…an impressively wide-ranging book covering epidemiology, medical history, economics, agricultural history, evolution, and architecture. Rosen marshals information from history, zoology, genetics, complexity theory, meteorology, and evolutionary history to present a fascinating account of the interrelationships between fleas, rats, bacteria, climate, and food supply…worth reading for the lively accounts of battle scenes and the movement of armies; sympathetic descriptions of early Christian debates about the nature of God and Christ alongside critiques of intelligent design; discussions of the structure of marble; explanations of the effects of bacteria on a flea’s stomach and appetite, and, ultimately, the effect all this had on an empire.”
Helen Blackman in The Journal of the American Medical Association

“Like dominos falling, a series of events that began in the latter part of the 4th century triggered the separation of the eastern and western portions of the Roman Empire. The Huns invaded Europe from the east and forced the Goths to flee across the Danube River into Roman territory in 376. The battle of Adrianople in 378 destroyed two thirds of the eastern Roman army and caused a definitive split of the east from the west. By the beginning of the 6th century, Justinian became emperor of the Eastern Roman Empire, and by 540, North Africa and most of Italy were under his control. But a new invader, Yersinia pestis, came to Egypt, and then to Constantinople in 542, and on to Western Europe and the Persian Empire. For the next two centuries, waves of plague struck throughout the Mediterranean, Western Europe, and the Middle East. The old Roman Empire and the Persian Empire were depopulated. Plague changed everything, and as it did again in the 14th century, it changed the course of history…Rosen’s knowledge of these events is remarkable. His explanations of the interaction of Y. pestis with the immune system and of bacterial pathogenesis provide insight into a killer that shaped history… Justinian’s Flea is a well-researched book that is also a pleasure to read, and I enthusiastically recommend it.”
Raymond J. Dattwyler, M.D. in The New England Journal of Medicine

"Don't charge William Rosen with lack of ambition. Instead of biography or the thin slice of the past that has become popular with history publishers, he presents us with no less than the foundations of the modern world, as built by a man and an insect. The result is largely successful and engaging. While the reader occasionally loses his bearings in an account that spans 10,000 miles, a dozen peoples, biology, architecture and the law, he is also amazed that Rosen packs it all into only 384 pages… [In] this widest of wide-ranging books, he leaves no cause unconsidered and eloquently connects a flea's bite 1,465 years ago with the world as it is today."
Jay Hancock in The Baltimore Sun

"...Rosen succeeds brilliantly. He writes what might be called champagne prose: it slips down quick and easy but carries a punch. He covers not just the centres but the extremities of knowledge: this book touches on gravity fields, early modern microscopes, late Roman cavalry tactics, and load patterns in the Hagia Sophia...He also covers the extremities of Eurasia, moving from monasteries in Dark Age Britain to civil war in China and brooding monotheists in the Arabian deserts - a geographic range that carries within it Justinianic ambitions. Sometimes, it is true, the trip resembles a driving holiday in Portugal - superb landscapes but almost no road signs - but the journey is always a fascinating one."
Simon Young in The Telegraph

"As a feat of scholarship alone this book is extraordinary, but what really impresses is the sense of ease its author manifests in whatever subject he enters. It's as if he'd been granted the freedom of Late Antiquity at birth. Furthermore, he allows himself space; when a subject requires explanation, and that in turn requires digression, he grants both. You never feel that he's indulging in scholarship for its own sake. I have to salute any author who can keep the reader enthralled by the intricacies of Byzantine architecture, let alone by protozoic metamorphosis -- and he does...Rosen's study comes very close to being a truly great work of history. His eloquence, wit, narrative skill, learning and (one dares to add) compassion, hoist this book above the miasma of its deeply sombre subject and make it, strangely, a joy."
Murrough O'Brien in The Independent

“This ambitious and learned book is destined to be a librarian's nightmare. How on earth to categorise it? Justinian's Flea is, among other things, a work of political, military, medical and cultural history. It may even have a reasonable claim to being a work of zoological history too...Mr Rosen argues his position methodically and thoughtfully. He has a lot of ground to cover and he will not be rushed. So there are chapters not only on Justinian and the plague but also on the migration of the Goths, Visigoths, Ostrogoths and Huns; on Byzantine architecture; on Roman law; on China and the silkworm; and on the emergence of Islam...All of this he deals with very well. Scholars may quibble with certain particulars but ordinary readers will be swept along by the strong current of Mr Rosen's good-natured erudition.”
The Economist

"In this eccentric and erudite book, in which a flea looms as large as an emperor, Rosen sets out to establish the forces that transformed the Mediterranean world of late antiquity into medieval Europe. Justinian's Flea is a massively ambitious work that covers a great deal of ground. It is a history of the eastern Roman empire and its many enemies, as well as a survey of the great city fo Constantinople, a new Rome straddling seven hills and smelling strongly of fermented fish sauce. This book also contains a detailed account of the evolution of the bubonic plague and how it weakened the empire's resistance to the conquering armies of Muhammad. It discusses how the Roman empire's collapse gave birth to the proto-nations within it, and how the rise of Islam helped to shape the identity of the European superstate of Christendom. [An] impressive study of the bubonic plague and its impact on history."
Ian Pindar in The Guardian

"A history of the Empire before Justinian took it over, [which] then runs confidently through to the last days that ended with the fall of Constantinople to the armies of Muhammad. Assertively modern in language and attitude, Rosen’s multi-disciplinary Byzantine history deals not only with fatal microbiology but also celebrates Justinian’s major achievements."
Iain Finlayson in The Times (London)

"Rosen] conveys the significance and excitement of Justinian’s achievements, from the building of Hagia Sophia to the codification of Roman law, without falling for all Procopius’s lurid gossip. He also does a good job in telling the scientific story of the plague... I found his account of how the plague organism developed, how it mutated and was transmitted to humans, and how we can still track its progress on the ground, a fascinating one."
Mary Beard in The Sunday Times

"Rosen relays eyewitness accounts of the Justinianic plague, with which he integrates the modern scientific understanding of Yersinia pestis and its carrier, the rat...Deeply steeped in the literature of late antiquity, Rosen wears his erudition lightly as he weaves interpretations into a fluid narrative of the era's geostrategic possibilities before the final onset of the Dark Ages."
Booklist

“Rosen absorbingly narrates the story of how the Byzantine Empire encountered the dangerous Y. pestis in A.D. 542 and suffered a bubonic plague pandemic foreshadowing its more famous successor eight centuries later… readers of Collapse and Guns, Germs, and Steel, Jared Diamond's grand narratives, will find this a welcome addendum.”
Publishers Weekly

“A polymathic account of the rise and reign of the Emperor Justinian (a.d. 527-565), whose greatest nemesis turned out to be a microscopic terror he could neither see nor identify… Rigorous, highly informative history written with passion, panache and an appealing bit of attitude.”
Kirkus Reviews (starred)

Selected Works

History, Science, Medicine
For fans of Microbe Hunters: The epic history of how antibiotics were born, saving millions of lives and creating a vast new industry known as Big Pharma. Miracle Cure explains why, given the complex nature of bacteria—and their ability to rapidly evolve into new forms—the only way to locate and test potential antibiotic strains is by large-scale, systematic, trial-and-error experimentation. Organizing that research needs large, well-funded organizations and businesses, and so our entire scientific-industrial complex, built around the pharmaceutical company, was born.
History, Science
The end of feudalism, and the beginning of European nation-states, against the background of a wrenching change in climate...the famine that marked the end of the Medieval Warm Period.
History, Economics, Science
A provocative examination of the most transformative event in human history: the Industrial Revolution. "A fascinating, wide-ranging narrative...A staggering work of epistemological research." KIRKUS REVIEWS (Starred review)
History, Medicine
A sweeping account of how nature's smallest organism brought down history's mightiest empire. "Eccentric and erudite...a massively ambitious work." THE GUARDIAN (London)

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