When COVID-19 first arrived last year, everyone’s go-to historical parallel was the 1918 influenza pandemic. Precisely because it was so fleeting, it’s hard to find evidence that it caused a sweeping reorientation of everyday life. In its wake, most people simply forgot what happened. Other global pathogens stayed longer and had much bigger impacts on society.

Consider what followed the double-shot of diseases that hit the Roman Empire: the Antonine Plague, which raged between the years of 165 and 180, and the Cyprian Plague, which hit in 249 and lingered into the 260s. At least one or both of these are believed to be ancestors of modern-day variola virus, better known as smallpox.

When these plagues arrived, Christianity was a fringe religion. The sociologist and religious scholar Rodney Stark has argued that the response to the outbreak among this small sect helped propel Christianity to dominance, destroying the older, pagan faiths along the way.