The Black Death of 1348-1350 is without a doubt the most celebrated case of bubonic plague. By the 14th century, Christian ships, designed to withstand the choppy waters of the Atlantic year-round, passed through the Strait of Gibraltar, carrying the disease into northern realms via the fleas of the black rats that had climbed aboard. Although areas with different ecologies responded to the plague with varying degrees of contagion, the pestilence, originating in China, wiped out at least one third of the population of Europe. In recent years, however, scholars have tended to downplay the demographic losses of the Black Death because, beginning almost a century before, the effects of an over-crowded Europe were already taking place as the failure of agricultural resources to meet the demands of a bloated population caused famine and scarcity, and consequently a decided plunge in the number of European inhabitants.
Muendel J. King Death: The Black Death and Its Aftermath in Late-Medieval England. JAMA. 1997;277(12):1007-1008. doi:10.1001/jama.1997.03540360075037