<P> The Great Plague, lasting from 1665 to 1666, was the last major epidemic of the bubonic plague to occur in England . It happened within the centuries - long time period of the Second Pandemic, an extended period of intermittent bubonic plague epidemics which began in Europe in 1347, the first year of the Black Death, an outbreak which included other forms such as pneumonic plague, and lasted until 1750 . </P> <P> The Great Plague killed an estimated 100,000 people--almost a quarter of London's population--in 18 months . The plague was caused by the Yersinia pestis bacterium, which is usually transmitted through the bite of an infected rat flea . </P>

When did the great plague start and end