Babylonian calendar
The
Babylonian calendar was a
lunisolar calendar with years consisting of 12
lunar months, each beginning when a new
crescent moon was first sighted low on the western horizon at sunset, plus an intercalary month inserted as needed by decree. This system came into use sometime before
2000 BC.
The names of the months were:
*
Nisanu*
Ayaru*
Simanu*
Du`uzu*
Abu*
Ululu*
Tashritu*
Arakhsamna*
Kislimu*
Tebetu*
Shabatu*
AdaruUntil the
fifth century BC the calendar was fully observational, but beginning about
499 BC the months began to be regulated by a
lunisolar cycle of 19 years equaling 235 months. Although usually called the
Metonic cycle,
Meton (
432 BC) probably learned of the cycle from the Babylonians. After no more than three isolated exceptions, by
380 BC the months of the calendar were regulated by the cycle without exception. Within the cycle of 19 years, the month
Adaru 2 was intercalated, except in the year that was number 17 in the cycle, when the month
Ululu 2 was inserted. During this period, the first day of each month (beginning at sunset) continued to be the day when a new crescent moon was first sighted—the calendar never used a specified number of days in any month.
*
Hebrew calendar*Parker, Richard A. and Waldo H. Dubberstein.
Babylonian Chronology 626 B.C.-A.D. 75. Providence, RI: Brown University Press, 1956.
