Coming Soon To A CPAN Near You!!! Sunday Letters are, to simplify, a representation of how long after January 1 the first sunday of the year falls. For example, the following table shows the Sunday Letters, given the day of the week of January 1: 1 January First Sunday Sunday Letter Sunday 1 January A Monday 7 January G Tuesday 6 January F Wednesday 5 January E Thursday 4 January D Friday 3 January C Saturday 2 January B In leap years, you have one sunday letter for the pre-leap-day portion of the year, and a different one for the rest of the year. This is because the sunday letter, combined with the day-of-year, can be used to figure out what day of the week you're on, and this gets screwed up in leap years after leap day. I have just uploaded to CPAN Date::SundayLetter, which calculates the sunday letters for any given year (after 1582). Eventually I'll have another algorithm in there for Julian calendar dates, since the formula ends up being slightly different. Sunday Letters are also very useful in one particular method for calculating the date of Easter. (And Passover, and Rosh Hashanah, and any other lunar-based event.) Rich -- And everyone said, "If we only live, We too will go to sea in a Sieve - To the hills of the Chankly Bore!" (The Jumblies, by Edward Lear)
