Anna ( and anyone else who is interested), The following is from the is from the GRS newsletter. Hope it helps. 1. How to Figure Birthdates >From "Compendium of Historical Sources" by Ronald Bremer Often tombstones have a notation such as: "Died 15 June 1872, Aged 77 years, 10 months, 3 days." How do you determine the correct birthdate? First of all, make the sequence read days, months, years: thus 15-6-1872 minus 3-10-77. Since the 10th month cannot be subtracted from the sixth, borrow 12 months from the year of death, making the year 1871 and the month 18. (If you borrow from the month to make days, borrow 30 days, even though the month might have 31.) The equation now looks like: 15-18-1871 minus 3-10-77. Begin the calculations on the right hand side. Therefore, 77 years from 1871 means that the person was born in 1794. Subtracting 10 months from 18 gives you eight months, or August. So the correct date of birth was 12 August 1794.