The Quechua would mix the ground bark of cinchona trees with sweetened water to offset the bark’s bitter taste, thus producing tonic water. Jesuit missionaries in the early 1600s brought this back to Rome, where quinine in unextracted form came into use to treat malaria, which was endemic to the swamps and marshes surrounding the city of Rome and responsible for the deaths of several popes, many cardinals and countless common Roman citizens.