Chapter 7 discusses the spread of vaccination in northern Europe. Familiarity with smallpox inoculation, its disadvantages as well as its advantages, assured a strong constituency of interest in the Netherlands, Germany and Scandinavia and a generally positive response to the potential of the new prophylaxis. Medical men in Germany, well-networked professionally, conducted trials of the new prophylaxis, rapidly achieved consensus as to its value and collaborated in extending it nationally. They invested culturally in vaccination, celebrating the ‘guardian pox’ in festivals and promoting a cult of Jenner. In the Netherlands, most German states and in the kingdoms of Denmark and Sweden, rulers acted on the advice of their physicians to endorse and support vaccination. Government officials and the clergy, Catholic as well as Lutheran, needed little prompting to assist in establishing it in their spheres of influence. Vaccination put down strong roots across northern Europe, becoming compulsory in Bavaria in 1805, Denmark in 1810–11 and Sweden in 1816.