Date: Sun, 19 Mar 2000 20:09:22 -0500 (EST) From: Russell Hendel < rhendel@mcs.drexel.edu> Subject: Re: Day 8 QUESTION: < < ...When did the Rabbi's sit down and agree... Today is Tuesday, Year 2346. Is there a date in history that our ancestors decided was a start date of the calender...> > ANSWER: There are only 2-3 basic rules governing the answer to this question During the time of the temples the Sanhedrin (the equivalant of our congress sat and reviewed WHEN the month and/or YEAR should begin each month. Some months were 29 days and some were 30; some years had 12 months and some had 13. While witnesses had to come and say they saw the moon, the final determination was made by the court. After the destruction of the temple our current calendar was 'fixed'-- based on a few simple rules given below. The purpose of these rules was to make calculations easy (See Rambam, Laws of Months Chap 6-10 for a more detailed computation). This is the same calendar that we use today. Although many programs exist for calendar making, these rules could easily be codified into an excel spreadsheet. The rules governing the calendar are the following: (a) months are 29 or 30 days; (b) years are 12 or 13 months; (c) The calendar works in cycles of 19 years with years 3,6,9,11,14,17 leap years; (d) the lunar month is 29 days, 12 hours and 793/1080ths of an hour (e) The first lunar month started on Monday 11 at night at 204/1080ths after the hour (f) The first month of the year is always 30 days, the next two months may be either both 29, both 30 or 29, for month 2 and 30 for month 3, and the remaining months alternate (29,30,...). (g) The laws governing the 2nd and 3rd month depend on the relative distance of the new year days in the 2 consecutive years (h) The declaration of WHEN the month begins is the same day as when the lunar conjunction occurs except in 4 cases. I note in passing that the "Monday 11PM 204/1080ths" time for the first month is 'fictitious'---it is a number that exists only for calculational purposes since all calculations are 'approximate'. The talmud refers to the first month in year 0 as the 'conjunction during nullility'. The time used (Monday 11 PM..) is based on the assumption that Adam was created on Friday (New Year 1) and the sun was created on Wednesday (6:00 PM). The calculations honor the two traditions that the world was created either in April or September. I hope this brief summary helps. If you need help in constructing a spreadsheet let me know offline Russell Jay Hendel; Phd ASA; Moderator Rashi is Simple, http://www.shamash.org/rashi/