The plague is a disease caused by a bacillus, Yersinia pestis, transmitted by the bite of an infected flea. ‘Plague’ identifies three main periods of the pandemic. It first appeared in the sixth century ce with several epidemics in Europe and the Near East lasting until the end of the eight century. The second pandemic—the Black Death—began in 1347 and killed up to half of the continent’s population. The last European outbreak was in Russia in 1770. The third pandemic began in China in 1890 and spread rapidly around the Pacific world. Improved sanitation, isolation, and new antibiotics help, but the plague still exists today.