Mongolian Biological Warfare

Black Death - the name haunts humanity to this day.  Europe, where the plague hit worse, killed 30 - 60% of the population.  Estimates of the death toll vary, ranging from 75 million to 200 million.  Most people already know this; however, one thing is often forgotten - Black Death's entry into European was an intentional act of biological warfare.  

Caffa is shown in the lower right-hand corner - Source: Encyclopaedia Judacia

The Islamic Mongolian Golden Horde which ruled central Asia, traditionally had an uneasy relationship with the Italian merchants which built the city of Caffa (also knowed Kaffa).  The contentious relationship boiled over in 1343 when a minor conflict involving Italians and Muslims turned violent leaving a Muslim dead.  The perpetrators of this escaped to Caffa where they received sanctuary.   Mongols commanded by Jani Beg was now enraged and laid siege to the Italian stronghold.  The siege ended in disaster for the Golden Horde with the arrival of Italian reinforcements slaughtering 15,000 Mongolian soldiers in February of the next year.  

Jani Beg, refusing to admit defeat, once again laid siege on the city in 1345 but was interrupted by the arrival of the Black Death.  In an effort to spread the disease to the population within the city, corpses of those who perished from the plague were placed on siege weapons and launched into the city.  Despite the Italians' best efforts to contain the disease by throwing the corpses into the sea, they were becoming overwhelmed.  One year later in 1347, the Italians began their exodus towards Italy in the face of the relentless onslaught of the Black Death.  (This event was recorded extensively by Gabriele De' Mussi, a notary from Picaenza.)  

On their journey home, the Italians made a stop at Constantinople inadvertently infecting the capital of the Byzantine Empire which began the spread of Black Death into Eastern Europe.  By the time they arrived in Sicily, off the coast of southern Italy, many of the sailors were dead or dying.  With this, the Black Death had reached the heart of Europe.  In three short years from 1347 to 1349, all of southern Europe was infected and by 1351, the entirety of Europe was under the shadow of the Black Death.  

A minor dispute between Italians and Muslims in a relatively insignificant section on the fringe of Europe had led to its greatest catastrophe.  European population would not recover for another 150 years.  This marked the first recorded use of a biological weapon and its effects were horrific.  A minority of scholars believe that the spread of Black Death from the Golden Horde to Caffa was accidentally done by rodents.  However, this view is unsubstantiated by historical evidence & implausible because the Mongolian encampment was over a kilometer away from the Caffa walls (rats rarely travel over 30 - 90m).  Because of this, the majority of scholars who have studied the events believe that Caffa was the gateway through which the Black Death entered Europe.  The second greatest plague in human history, begun by a ruthless act from a barbaric khan.

The Spread of Black Death in Europe 1347 - 1352 - Source: Princeton University