Mesopotamia: The Birth of the Month

The ancient Sumerians and Babylonians were the first to develop a structured lunisolar calendar. This system, which dates back to the 3rd millennium BCE, laid the groundwork for the Hebrew, Greek, and even the modern Gregorian calendars.

The Lunar Month

The Mesopotamian year was based on the phases of the moon. Each month began with the first sighting of the new crescent moon. Because a lunar month is about 29.5 days, their year consisted of 12 months, totaling 354 days.

The Intercalary Month

Since a lunar year is 11 days shorter than a solar year, the seasons would quickly drift out of sync with the calendar. To fix this, the Babylonians eventually developed a 19-year cycle (the **Metonic Cycle**) where 7 extra "intercalary" months were added over 19 years to keep the harvest festivals aligned with the sun.

Naming the Months

Many of the Babylonian month names, such as *Nisanu* and *Tashritu*, were adopted by the Jewish people during the Babylonian Exile and remain in use in the Hebrew calendar today as *Nisan* and *Tishrei*.

Conclusion

The Mesopotamian calendar was the first attempt to reconcile the conflicting cycles of the moon and the sun. On the Epoch Clock, we follow a purely solar-based digital count, but the very existence of "months" in our lives is a legacy of the priests of ancient Babylon.