DateTime::Calendar::Hebrew is the implementation of the Hebrew calendar. Read
on for more details on the Hebrew calendar.

The Hebrew/Jewish calendar is a Luni-Solar calendar. Torah Law mandates that
months are Lunar. The first day of a month coincides with the new moon in
Jerusalem. (In ancient times, this was determined by witnesses. Read the books
in the bibliography for more info). The Torah also mandates that certain
holidays must occur in certain seasons. Seasons are solar, so a calendar that
can work with lunar & solar events is needed.

WWW: http://datetime.perl.org/