I think that there is an error in TMG's handling of Old Style dates, both in the program and in the help system. Could someone look over my logic to make sure I am not missing something? Let's start with a very clear description of what the notations mean in this context. (Yes, I know that there is some confusion about this.) “George Washington was born 11 February 1731/2, which means that the year was still 1731 if the New Year was reckoned as not beginning until 25 March, but that the year was already 1732 if it had begun 1 January. That is, it was 1731 Old Style, or 1732 New Style. […] The date 11 February 1731, Old Style, is identical with 22 February 1732, New Style.” (Jacobus 1980*) What is important for this discussion is that the OS year comes before the slash and the NS year (1 year later) comes after the slash. The 11-day difference is irrelevant for present purposes. So, the date 24 Feb 1690/91 is in year 1690 OS and in year 1691 NS. However, when you enter the following date in a TMG date field, "recognizable" by TMG: 24 Feb 1690 OS TMG incorrectly converts that to: 24 Feb 1689/90 [24 Feb 1690/91 is correct]. Or when you enter 24 Feb 1691 OS TMG incorrectly converts that to: 24 Feb 1690/91 [24 Feb 1691/92 is correct]. The error in TMG appears to be that when a date in OS notation is entered, in the conversion to the slash notation the OS year is incorrectly placed*after* the slash and the NS year (incorrectly 1 year*earlier*) isincorrectly placed*before* the slash. Similarly, in the TMG article on “Date Formats” in the help system: “Recognizable date forms include: 24 Feb 1691 OS 24 Feb 1690/1 24 Feb 1690-1 24 Feb 1690 .. 1 In the above examples, if you enter the date in any of these formats, TMG will enter 24 Feb 1690/91.” And indeed it does, incorrectly. A good reminder that (1) one should keep a verbatim record of the date as stated in the source, and (2) one should not blindly trust date or calendar converters. N.B. My old style date range is set at 1583 to 1752 (Preferences > Program Options > General). I am running TMG 9.03. Barbara * Jacobus, Donald Lines. "Genealogy and Chronology." In Genealogical Research: Methods and Sources, edited by Milton Rubincam, 27-37. Rev. ed. Vol. 1. Washington, DC: American Society of Genealogists, 1980, 33-34 -- Barbara Levergood levergood@att.net (=^·^=)~