Guest post by Seph Gonzalez
Calendars in Mesopotamia were primarily lunar in nature, with certain solar phenomenon, including the solstices and equinoxes, also being observed. Both the length of a given year and the duration of its constituent months were determined by the phases of the moon, and each year consisted of twelve standard months that varied in length between 28 and 30 days. Every new year began in the spring, with the first sighting of a waxing lunar crescent following the vernal equinox, stabilizing New Year’s Day somewhere between 22 March and 21 April. There is no evidence of a standardized system for intercalating months to account for equinoctial precession prior to 500 BCE, but both the Sumerians and Semites did make use of an intercalary month when it became visibly apparent that the first month of the new year was going to arrive before the vernal equinox had occurred.
Generally, the name of the intercalary month is devised by appending the words “second” (arkû) or “intercalary” (diri) to the name of the twelfth month. At the city of Ur, for example, the month itidiri-ezem-dme-ki-ĝal₂ comes into use during the Ur-III Period as an intercalary month, while at the cities of Nippur and Umma the month itidiri-še-kiĝ₂-ku₅ became the standard intercalary month during this period. In Babylonia and Assyria, which had adopted the Standard Mesopotamian Calendar by 1400 BCE and 1100 BCE respectively, the intercalary month was called Araḫ Addaru Arkû, and it was intercalated whenever it was observed that the advent of the new year had fallen out of alignment with the vernal equinox.
Around 500 BCE however, the Achaemenids came to power in Babylonia and implemented a new 19-year cycle called the Metonic cycle, named for Meton of Athens, who likely learned about it while visiting Babylonia. The Metonic cycle recognized that, over the course of 19 years, 235 lunar months occurred. Using this knowledge, the Achaemenid Babylonians devised a repeating cycle of 12 “short” years (consisting of 12 months each), alongside 7 “long” years (consisting of 13 months each) that could be repeated every 19 years. The Achaemenid Babylonians also determined that years 3, 6, 8, 11, 14, 17, and 19 of the cycle were the “long” years, while the rest were “short” years.
Armed with this new repeating calendar, the Achaemenid Babylonians determined that the intercalary month of years 3, 6, 8, 11, 14, and 19 were to retain the old name of Araḫ Addaru Arkû, but that the intercalary month of year 17 was to be called Araḫ Ulūlu Arkû. It is uncertain why this change was implemented, although it might have to do with the second full moon—today called a Blue Moon—that occurs near the end of March on these years. It is equally uncertain whether the “second” Ulūluoccurred after month twelve or month six, the standard placement of Ulūlu in the calendar.
As can no doubt be gleamed from the explanation above, the current month is intercalary. However, it is also the final month of our current Metonic cycle, meaning that a new Metonic cycle will begin on 13 April 2021. The chart below outlines the important data for each of the coming years, including how many lunar months they contain, what Gregorian month the year starts in, which year of the Metonic cycle they correspond to, and what the intercalary month will be called:
With the introductory material squared away, we now move on to the actual substance of this article. The month of Araḫ Addaru Arkûofficially begins on the evening of 13 March, with a 1% waxing lunar crescent. Dawn of the following morning, 14 March, marks the advent of Day 01. Unlike the previous months, there were no special festivals performed during this lunar cycle. Instead, the standard practice across Mesopotamia was to repeat the festivals from the prior month. However, in the interest of keeping each entry of this series insightful, I will focus instead on the series of festivals and holidays that were celebrated every single month according to the various calendars in use across Mesopotamia.
We will open with a series of special observances for the gods and goddesses of Babylonia.
- Days 4 (18 March), 8 (22 March), and 17 (31 March) featured special observances for the supreme-god of Babylonia, Marduk, and his son, the god of wisdom and writing, Nabû.
- Day 18 (01 April) was dedicated to the lunar-god Sîn and his son, the solar-god Shamash.
- Day 22 (05 April) was designated for the goddess Bēlet-Ekalli, the “Lady of the Palace,” an Akkadization of the Sumerian: nin-e₂-gal, an epithet of the goddesses Inana or Ishtar. Day 22 also bears the enigmatic title of “day of the nikkassu of Sîn and Shamash,” where the word nikkassu is usually translated “accountancy,” but can also be used to identify a symbol (šurinnu) associated with the sun-god Shamash. Perhaps this day marked a special occasion during which the nikkassu of Shamash and the šurinnu of Sîn were revealed in their temples at Babylon?
- A two-day festival occurred on Days 23 (06 April) and 24 (07 April). The festival was dedicated to Shamash and Adad, two gods who are, elsewhere, associated with the divinatory arts.\1]) It is not unreasonable that the 23rd and 24th days of the month were reserved for some form of divination.
- Day 24 also featured a festival for Bēl-Ekalli and Bēlet-Ekalli, the Lord and Lady of the Palace, whose identities are not given but might represent Marduk and his wife Ṣarpānītum.
- Day 27 (10 April) is dedicated to the god of wisdom and writing, Nabû, although the significance of this occasion is not provided.
To conclude this article, it is also worth mentioning that the standard eššeššu and kispū festivals were also celebrated during the intercalary month. The eššeššu festival of Araḫ Addaru Arkû occurred on the evening of Day 14 (28 March), coinciding with the full moon’s radiance. The kispū festival, meanwhile, closed out the month and began at dusk on Day 29 (12 April), coinciding with the new moon’s darkness.