What you feel are the three most impactful or consequential epidemics/plagues in the history of Western Civilization up to the 16th century? What similarities and differences did they have in their societal impacts (beyond the symptoms or numbers of afflicted)? Lastly, of the pandemics you mentioned, what do you think is the single most important development/innovation/change to come from any/all of these epidemics (in the history of Western Civilization)?