Editing Roman Empire (section)

===Health and disease===
{{Further|Disease in Imperial Rome|Antonine plague|Plague of Cyprian}}
[[Epidemics]] were common in the ancient world, and occasional [[pandemic]]s in the Empire killed millions. The Roman population was unhealthy. About 20 percent—a large percentage by ancient standards—lived in cities, Rome being the largest. The cities were a "demographic sink": the death rate exceeded the birth rate and constant immigration was necessary to maintain the population. Average lifespan is estimated at the mid-twenties, and perhaps more than half of children died before reaching adulthood. Dense urban populations and [[Sanitation in ancient Rome|poor sanitation]] contributed to disease. Land and sea connections facilitated and sped the transfer of infectious diseases across the empire's territories. The rich were not immune; only two of emperor Marcus Aurelius's fourteen children are known to have reached adulthood.<ref name="Harper">{{Cite book |last=Harper |first=Kyle |title=The Fate of Rome |date=2017 |publisher=Princeton University Press |isbn=978-0-6911-6683-4 |pages=10, 30–31, 67–91}}</ref>

The importance of a good diet to health was recognized by medical writers such as [[Galen]] (2nd century). Views on nutrition were influenced by beliefs like [[humoral theory]].<ref>{{Cite book |last=Grant |first=Mark |title=Galen on Food and Diet |date=2000 |publisher=Routledge |pages=7, 11}}</ref> A good indicator of nutrition and disease burden is average height: the average Roman was shorter in stature than the population of pre-Roman Italian societies and medieval Europe.<ref>{{Harvp|Harper|2017|pp=75–79}}; {{Cite journal |last1=Koepke |first1=Nikola |last2=Baten |first2=Joerg |date=1 April 2005 |title=The biological standard of living in Europe during the last two millennia |journal=European Review of Economic History |volume=9 |issue=1 |doi=10.1017/S1361491604001388 |hdl-access=free |pages=61–95 |hdl=10419/47594}}</ref>