 Complete the following phrase:  William H. McNeill, a world historian, noted in chapter three of his book Plagues and Peoples 1976 that the Roman Empire suffered the severe and protracted Antonine Plague starting around 165 AD. For about twenty years, waves of one or more diseases, possibly the first epidemics of smallpox and measles, swept through the Empire, ultimately killing about half the population. Similar epidemics, such as the 