Historical records allow us to reconstruct patterns of disease spread in the past, in some cases going back hundreds of years. The questions we can address depend on the available data, which has varied enormously over time. I will present data, going back as far as 1348, which we have acquired and studied at McMaster in the last few years. I will discuss the strengths and limitations of the various types of data for mechanistic modelling, and how these data have so far contributed to improving our understanding of pandemics of plague, cholera, influenza, and COVID-19.