John Graunt (1620-1674) was one of the first demographers. Born in London, Graunt, along with Sir William Petty, developed early human statistical and census methods that later provided a framework for modern demography. His book Natural and Political Observations ... upon the Bills of Mortality (1662) used analysis of the mortality rolls in early modern London as Charles II and other officials attempted to create a system to warn of the onset and spread of bubonic plague in the city. Though the system was never truly created, Graunt's work in studying the rolls resulted in the first statistically-based estimation of the population of London. The erudition of the Observations led Graunt to the Royal Society, where he presented his work and was subsequently elected a fellow. Graunt died, reportedly of jaundice and liver disease, in April 1674 in London.