Smallpox was a deadly epidemic disease that raged sporadically in early modern Europe. But great progress was made in the fight against this disease after British physician Edward Jenner (1749-1823) discovered that patients who had contracted the harmless cowpox developed immunity to the fatal effects of smallpox. Cowpox immunization was subsequently introduced in 1796. The method initially caused controversy but was eventually accepted, significantly reducing fatalities. This etching shows a child being vaccinated against smallpox.