You cannot "tweak" it, but you could do what I have been doing in all of my campaigns: simply saving before hitting End Turn and reloading, unless of course, you consider that cheating. As for the average lifespan of a person during Antiquity, I have hard time believing it. Herodotus is my favorite Classical historian as his accuracy and objectivity is mostly unsurpassed by his contemporaries, but he is not faultless. Just read his descriptions of India... they sound more like fairy tales or fantasy books than a historical treatise.
In the Antiquity, the average lifespan for a Roman or a Greek was about 50 years(that's not counting the 40-30% infant mortality rate), according to most modern historians, doctors and archaeologists. Media, both modern and ancient, like nothing more than writing about the isolated and rare cases of a person reaching extraordinary age while failing to mention the millions that die in their 40's 30's or 50's. Not to mention, that Herodotus often wrote about important people. Important people were often of the upper classes of society. An important person from the upper class had more chances of reaching old age if he/she was not assassinated or killed in battle.
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