Biological warfare is a practice known from antiquity. The titular character of Philoctetes, Sophocles’ 409 BC play, is a Greek hero who suffers from a festering leg wound caused by a poisoned Trojan arrow. The ancient use of poisoned arrows in battle is also attested by the Greek historian Herodotus, who, in the 5th century BC, wrote about Scythian archers’ use of arrows steeped in a toxic mixture comprising the venom of adders, blood, and fecal matter. Due to the snake venom, the resulting poison would have attacked the central nervous system, probably causing respiratory failure. The other ingredients, in what can only be described as overkill, would have introduced tetanus and gangrene bacteria into the body of the targeted enemy.
Snakes also played a role in a biological warfare strategy employed by Hannibal, the Carthaginian general and statesman, during his 190 BC naval battle against the Roman allied city-state of Pergamon and its ruler, Eumenes II. Hannibal had jars filled with live, poisonous snakes stored aboard his ships. When the Pergamene ships came within striking distance, Hannibal’s crews launched the jars, which shattered upon the decks of the enemy vessels, unleashing their deadly, undoubtedly angry, contents.
However, none of these ancient tactics are known to have had as wide an impact as that employed by Jani Beg, Khan of the Golden Horde, during the 1346 Mongol siege against the Genoese outpost at Caffa (modern Feodosia, Ukraine) on the Black Sea. This siege was a significant, possibly pivotal, event in the spread of the Black Death from its point of origin in Central or East Asia to Europe, the Middle East, and North Africa.
According to the Istoria de Morbo sive Mortalitate quae fuit Anno Dni MCCCXLVIII (“History of the Disease, or The Great Dying of the Year of our Lord 1348”), a 1348 history of the Black Death by Gabriele de’ Mussi, a notary from Piacenza, the Mongols used a trebuchet to fling the corpses of their own dead over Caffa’s fortified city walls. This tactic was neither new, nor was it unique to the Mongols. By 1346, using siege engines to launch human corpses, animal carcasses, and excrement was an established method of waging both biological and psychological warfare on castles and other walled settlements.
What was new was the mysterious illness that had killed the Mongol soldiers whose bodies were used as projectiles. In addition, the beleaguered Genoese were powerful, highly mobile merchants who had made Caffa the primary trade hub on the Black Sea and the location of Europe’s largest slave market. These merchants traversed international trade routes, landed at ports all over their known world, and carried the disease back with them to the Mediterranean Basin.
The first and most deadly wave of the Black Death ravaged Europe, the Middle East, and North Africa between 1346 and 1353, killing approximately half of the population in each place. It was spread along international trade routes, most rapidly by sea, and along religious pilgrimage routes, such as those to the Islamic site of Mecca in Arabia and to the Christian Santiago de Compostela in Spain. Subsequent waves of the pandemic would hit afflicted regions periodically for several centuries, making population replenishment slow and difficult.
That said, the Black Death also resulted in significant, positive socio-cultural changes. It broke down the rigid tripartite Medieval social order, increased the social mobility of the European lower classes, hastened the end of the Medieval epoch, and set the stage for the achievements of the Renaissance and the Age of Enlightenment.
Historians still debate the precise weight of the Caffa siege in the spread of the Black Death, as there were certainly other lines of transmission, including from other sources in the same region. If the siege at Caffa had never happened, then it is possible that the Black Death might have run much the same course. However, it is clear that the biological warfare carried out at Caffa lit one of the fuses that set off a massive pandemic powder keg.