the Hebrew Calendar
The Jewish calendar, derived from the ancient Hebrew
calendar, has remained unchanged since about AD 900.
It is the official calendar of the modern state of
Israel and is used by Jewish people throughout the
world as a religious calendar. The starting point of
Hebrew chronology is the year 3761 BC, the date for
the creation of the world as described in the Old
Testament. The Jewish calendar is lunisolar, based on
lunar months of 29 days alternating with 30 days. An
extra month is intercalated every 3 years, based on a
cycle of 19 years. Dates of the Jewish calendar are
designated AM (Latin anno mundi,"the year of the
world") and BCE (before the common era).