If the only source for dates of birth and death are a gravestone and, say, the birth date is calculable because chiseled on the gravestone is how many years, months, and days that person lived, how sure can I be if the length of life spanned before and after the correction of the calendar in the 1700s? If unanswerable, is the best I can do is to put an estimated date of birth without knowing what system of time the maker of the gravestone was using?
How many profiles would this affect? Hundreds? Thousands?