Life expectancy is heavily skewed by infant mortality, which was of course rampant. If you made it past your tenth birthday, you had a 50% chance of making it

Life expectancy is heavily skewed by infant mortality, which was of course rampant. If you made it past your tenth birthday, you had a 50% chance of making it to 50, and a 25% chance of making it to 65. En masse, that makes for an amply large population of people in the age range for dementia to draw conclusions. https://en.m.wikipedia.org/wiki/Demography_of_the_Roman_Empire https://en.m.wikipedia.org/wiki/Demography_of_the_Roman_Empi...