In connection with the COVID-19 epidemic, there has also been some interest in historical outbreaks of different diseases. Historically speaking, it can be argued that epidemics have been common rather than extraordinary, and quite early on in history, some epidemics have turned into global events. The aim of this essay is to provide a certain overview of previous notions concerning the spread of diseases, showing how, despite the undoubtedly remarkable development of medical science, perceptions of infectious diseases and methods of combating them have remained surprisingly similar throughout many centuries. In this essay, approaches of the early modern period in particular regarding the nature of the plague are discussed, drawing on the work of John Allen (ca. 1660–1741) and Adam von Lebenwaldt (1624–1696), who had first-hand experience with the plague in the context of their medical practice. The text also briefly touches on the question of the origin of the plague and the mechanisms of its spread, based on Aristotle’s theory of elements as well as the views developed by Athanasius Kircher, which in a sense resemble (proto)bacterial theory.