What two possible causes does boccaccio suggest for such a terrible event?

In "The Decameron," Boccaccio suggests two possible causes for the terrible events surrounding the Black Death: divine punishment and natural phenomena. He implies that the plague may be a form of divine retribution for humanity's sins, reflecting a moral interpretation of suffering. Alternatively, he also acknowledges the role of environmental factors, such as poor air quality and unsanitary conditions, contributing to the spread of disease. Through these explanations, Boccaccio highlights the interplay between human behavior and the natural world in the face of catastrophe.