End of a Pandemic? Contemporary Explanations for the End of Plague in 18th‑Century England

Abstract

The great plague in London in 1665 was the last in a series of epidemics that had begun with the Black Death in the 14th century. Plagues continued elsewhere in Europe into the 18th century, but after 1679 no cases of plague were reported in England at all. The disease seemed to have disappeared. How could that be explained? The purpose of this paper is to discover when contemporaries began to think that plague had gone for good, and why they thought that had happened. The paper falls into two parts. The first concentrates on the decade of the 1720s, when plague was expected to come from Marseilles and never arrived. In the space of a few months there was fierce and concentrated public debate about a new Quarantine Act to be enforced if an epidemic developed, much of it arguing that the Act was unnecessary because plague was plainly not contagious at all. It depended wholly on local environments, and in England they had been improving ever since the Great Fire of London. The second part of the paper takes the story forward into the later 18th century, when there was no longer much dispute that plague was indeed contagious, but it was confidently supposed that England now enjoyed the double protection of further environmental improvement at home combined with effective quarantine of shipping abroad, especially in the Mediterranean. Over the century, contending explanations for plague were debated, interpretations of the past disputed and sometimes falsified, and expectations and ambitions for the future remodelled, because one epidemic threat had disappeared for good.