This is the first day of the Muslim New Year, and of the month of Muharram in the year 1431. The day actually began at sunset on the 17th, provided the young moon - just past "new" - was visible in the Middle East. Closely tied to the lunar cycle, the Muslim lunar year is about 354 days long, so the first day moves about 11 days earlier each year. Next year's Muslim New Year will begin Dec. 7 on the western (Gregorian) calendar.

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