Babylonian calendar

The Babylonian calendar was a lunisolar calendar used in Mesopotamia from around the 2nd millennium BC until the Seleucid Era (294 BC), and it was specifically used in Babylon from the Old Babylonian Period (1780s BC) until the Seleucid Era.

In the Seleucid Era it was reformed as "Greek time", Anno Graecorum was introduced and used in the Middle East and Egypt until the middle of the first millennium when the First Council of Nicaea AD 325 defined the Church year based on the Roman early Julian calendar. As Anno Graecorum formed the basis for time references in the Bible and spread westward, it rather increased the Babylonian calendars importance. The Babylonian calendar is also partly reflected in calendars in South and East Asia and the Islamic calendar as well as Iranian calendars. The Julian calendar inherited the definitions of the 12 month system, week, hour etc. from the Babylonian calendar and the current Jewish calendar can be seen as a slightly modified Babylonian calendar that still exists today and is practised, but with Anno Mundi Livryat haOlam year calculation since the creation of the world. Today's global time system UTC (Gregorian calendar) therefore has its main structure inherited from the Babylonian calendar.

The Julian calendars have their month definitions in tabular form while the Babylonian calendar, the Jewish calendar, and the Muslim calendar have their months defined by the appearance of the new moon and Iranian calendars by solstice.

The civil lunisolar calendar was used contemporaneously with an administrative calendar of 360 days, with the latter used only in fiscal or astronomical contexts.^[1] The lunisolar calendar descends from an older Sumerian calendar used in the 4th and 3rd millennium BC.^[2]

The civil lunisolar calendar had 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, at first by decree and then later systematically according to what is now known as the Metonic cycle.^[3]

Month names from the Babylonian calendar appear in the Hebrew calendar, Assyrian calendar, Syriac calendar, Old Persian calendar, and Turkish calendar.

^ Brack-Bernsen, Lis (2007). "The 360-Day Year in Mesopotamia". In Steele, John M. (ed.). Calendars and Years: Astronomy and Time in the Ancient Near East. Oxbow Books. pp. 83–100. ISBN 978-1-84217-302-2.
^ Sharlach, Tonia (2013-08-29). "Calendars and Counting". In Crawford, Harriet (ed.). The Sumerian World. Routledge. pp. 311–318. ISBN 978-1-136-21912-2.
^ Britton, John P. (2007). "Calendars, Intercalations and Year-Lengths in Mesopotamian Astronomy". In Steele, John M. (ed.). Calendars and Years: Astronomy and Time in the Ancient Near East. Oxbow Books. pp. 115–132. ISBN 978-1-84217-302-2.

[brack-bernsen-1] Brack-Bernsen, Lis (2007). "The 360-Day Year in Mesopotamia". In Steele, John M. (ed.). Calendars and Years: Astronomy and Time in the Ancient Near East. Oxbow Books. pp. 83–100. ISBN 978-1-84217-302-2.

[2] Sharlach, Tonia (2013-08-29). "Calendars and Counting". In Crawford, Harriet (ed.). The Sumerian World. Routledge. pp. 311–318. ISBN 978-1-136-21912-2.

[britton-3] Britton, John P. (2007). "Calendars, Intercalations and Year-Lengths in Mesopotamian Astronomy". In Steele, John M. (ed.). Calendars and Years: Astronomy and Time in the Ancient Near East. Oxbow Books. pp. 115–132. ISBN 978-1-84217-302-2.

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