Elliott Bignell's Reviews > Justinian’s Flea: Plague, Empire, and the Birth of Europe

Long fascinated with the staggering speed at which early Islam expanded, I found that this book fills in several empty tiles in the puzzle. While historians, including those sympathetic to Islam, tend to focus on decisive battles like Badr and Yarmuk, it seems strange that a small cadre of converts from a remote desert fastness could by force of arms alone have conquered lands from the Atlantic to the Chinese border, almost as fast a one can walk the distance, against the resistance of Byzantines and Sassanids. Islam's relative tolerance must have attracted the many heretical sects along the way, but this can hardly explain the speed - how could they have known? A key element in understanding how this apparent contradiction came to pass is Justinian's Flea - the vector of what came to be known as the Black Death.

The book compiles details ranging from the identities of the confusion of tribes menacing the late classical world to the biology of the plague organism, Yersinia pestis. Indeed, if I have a complaint it is that the sudden switch from history to evolution is somewhat jarring. Nevertheless, it is compellingly written and uniformly fascinating. The descriptions of plague are a horror. An unusual disease, it is like Ebola a zoonosis, infecting non-human animal hosts in the wild form. Unfortunately for humans, it infects the rat, our constant companion, and at some stage developed the capacity to spread itself around by killing the rats while at the same time driving their fleas insane with hunger. It literally starves the flea by preventing it from swallowing, driving it to bite everything it can find and so spread its payload, the pathogen. An epidemic and population crash among infected rats is followed by an epidemic among humans, and one of uncommon lethality at that. An epidemic in its natural host will burn out by eating away the ground it stands on; a zoonosis knows no such restraints.

Worse, as it is not spread human-to-human, most countermeasures are useless. Monasteries, although isolated, suffered worst of all. The young were disproportionately struck in second and later waves as the old tended to have acquired immunity by surviving earlier epidemics. And for history it is of crucial importance that the Justinian Plague hit the Greeks and Persians just as the Roman Empire had mostly been reunited. Trade spread the plague around the Mediterranean in wave after wave, decimating the military-age population just as the two Empires were fighting each other to exhaustion. They retreated from the Arabian peninsula, and in only a decade a Prophet was born. His religion expanded into the vacuum like an explosion and the Middle Ages commenced, Europe fragmenting into fractious nations and China retrenching behind its Wall.

This is Rosen's model of history, and it seems compelling. It certainly solves an apparent mystery, which may be reason to be cautious. Strikingly, this is the author's first book, despite being a publishing executive. It is a stunning debut.