Fires are often seen as a constant in early modern European towns, changing only in the modern era when inflammable building materials replaced wood. This article argues that the incidence, nature and risk of fire shifted repeatedly over time. Fire danger was determined not only by building materials but also by forms of construction, by the everyday uses people made of flame and by wider factors such as climatic variation and shifts in world trade and consumer demand. It was influenced by urban social and political change, including the way governments and populations responded to the risk. Responses to new fire dangers in turn helped change the way urban government functioned.