The development of a calendar is vital for the study of chronology, since this is concerned with reckoning time by regular divisions, or periods, and using these to date events. It is essential, too, for any civilization that needs to measure periods for agricultural, business, domestic, or other reasons. The first practical calendar to evolve from these requirements was the Dwarven, and it was this that early mankind developed into the archaic calendar that served the empire for more than 1,500 years. The modern calendar was a further improvement and has been almost universally adopted because it satisfactorily draws into one system the dating of religious festivals based on the phases of the Moon and seasonal activities determined by the movement of the Sun. Such a calendar system is complex,since the periods of the Moon's phases and the Sun's motion are incompatible; but by adopting regular cycles of days and comparatively simple rules for their application, the calendar provides a year with an error of less than half a minute.

Astrologers eventually worked out a 19-year cycle in which there were twelve years with twelve months each and seven years with thirteen months each. The thirteenth month was inserted in a fixed pattern that kept cycles of the moon and sun even. Similar calendars were then adopted in many places near the City of Ur.

Days of the Week

Days of the week number 7 and each is devoted to a particular deity. A day begins at sunset and continues until sunset 24 hrs later. The Day of:

• 1. Nergal
• 2. Shamash
• 3. Sin
• 4. Ea
• 5. Anu
• 6. Hadad
• 7. Mammi

Months

Most years now consist of twelve lunar months. Beginning with Tishri, they are either thirty or twenty-nine days long. With these lengths, months approximate the mean period of the lunation cycle. Month names are Tishri, Heshbanda, Kish, Tirrur, Shebbet, Anshar, Ninsan, Kishyar, Shakkan, Dammuz, Avad and Enlil.

Heshbanda and Kish have a varying number of days. In a "complete" year Heshbanda has thirty days rather than twenty-nine. In a "deficient" year Kish has twenty-nine days rather than thirty. With these exceptions, month lengths alternate between twenty-nine and thirty days. Twelve lunar cycles are about eleven days short of a solar year. But every nineteen years, solar and lunar cycles repeat a phase relationship to each other. This is called the Ishzumic Cycle after an astrologer named Ishzum, though this fact had been known before his time by astronomers. To keep in long-term phase with the solar year, seven extra months (named Anshar II) are added to the calendar every nineteen years. This procedure assures that religious festivals will occur in their appropriate seasons. The calendar numbers years from what we believe to be the time when the Gods gave the Rule of Law to the first God-King .

 

1) Ninsan...........March-April.......... ...The Huntress

2) Kishyar..........April-May......... . .....The Serpent

3) Shakkan..........May-June........... ... ..The Phoenix 

4) Dammuz.........June-July............... ..The Hero

5) Avad..............July-August......... . ...The Magus

6) Enlil..............August-September.... .The Djinn

7) Tishri.............September-October.. .The Griffin

8) Heshbanda.......October-November... The Scorpion

9) Kish...............November-December..The Jackal

10) Tirrur..........December-January... ..The Serpent

11) Shebbet.........January-February.... ..The Sphinx

12) Anshar*........February-March...... ..The King

 * and Thirteenth

  

  

 

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