Pandemics can influence and radically alter habits and practices of entire populations. Billions of people have personally tested this phenomenon during the current Coronavirus Disease 2019 (COVID-19) crisis. History knows numerous signs of behavioral practice changes that can be attributed to pandemics, such as the bubonic plague that devastated medieval Europe in the mid-14th century, upsetting many sectors of civil life, or the pestilence that ravaged the Byzantine Empire during the reign of Justinian (mid-sixth century C.E.), even forcing the Goths and the Byzantines to suspend the war fought on the Apennine Peninsula.
Like other catastrophes, pandemics can be critical and polarizing events that generate societal changes beyond the immediate, health-centered issues. Some historical pandemics also had considerable religious consequences: They fueled religious radicalism, encouraged reform movements, and inspired theological discourse. One ancient pandemic even helped to establish the Christian rite of baptism administered to little children and infants—a practice not attested in early Christian communities until the late second century.1