||Until the modern era, human use of toxic
weapons -- biological or chemical -- was sporadic, unorganized and often inadvertent. One
instance of its impromptu use, however, set off the Great Plague of the 14th century,
which killed a third of the population of Europe. A Mongol army besieging the Genoan
trading outpost at Caffa in the Crimea (1346-1347) suffered an outbreak of the plague,
apparently of natural cause. Using the plague-infected corpses of their comrades as
biological weapons, the Mongols catapulted them over the walls of Caffa.
www.news.cornell.edu/Chronicle/99/11.4.99/bio_warfare.htmlThis tactical strategy was a great success. The Genoans, who were
soon decimated by the plague, fled Caffa by sea -- but they took the plague with them,
stopping in Naples long enough to establish the plague there, and then going on to Genoa.
From Caffa, Naples and Genoa, the plague spread throughout Europe.