A week or so ago, I talked about the Roman calendar, but they were by no means the only ones who used the cyclic nature of the moon’s phases to measure time. In fact, as in many other fields of scientific endeavour, the Romans probably based their first calendar on one of the Greek ones. The situation in Classical Greece wasn’t entirely straightforward: several different calendars
were used, even by neighbouring states. In the fourth and fifth centuries BCE, the small region of Attica alone had three different calendars, the most long-standing of which measured time by the moon, with twelve lunar months each year, plus a thirteenth month whenever it was needed to keep the months in line with the seasons. Each month started with the first sighting of the new moon, and the year began in the summer, when the first new moon after the mid-summer solstice was seen. Many other classical Greek states also based their calendar on the cycles of the moon, but most began their year in the autumn or winter, so there was little correlation in dates from one place to another.
In recognising a useful time system and adapting it for their own purposes, the Romans were repeating an earlier pattern: it’s more than likely that the Greek calendars were themselves largely based on the Babylonian one, which by the time of Archaic Greece was also a lunisolar one. Babylon by then was already an ancient civilisation, and starting each month at the first sighting of the new moon was a long-standing tradition, learned from the Sumerians, who we know developed a calendar of this type around 2000 BCE. Babylon started the year in the spring, and each day began at sunset.
Babylon’s lunisolar calendar gradually fell out of use during the first few centuries CE. But during the exile of the Hebrew people in Babylon, in the sixth century BCE, they adopted features of this calendar, and to this day the Jewish calendar is a lunisolar calendar, where each day begins at sunset, and the names of the months are derived from the Babylonian ones. Interestingly, Rosh Hashanah, the Jewish New Year, is celebrated in the autumn, and this is when the number of the year changes. But the ecclesiastical, or festival, year starts in spring, with the month of Nisan, just as Nisanu was the first, spring-time, month of the Babylonian calendar.
Although there is archaeological evidence that the Babylonians originally began each month when the designated witnesses first spotted the tiny crescent of the new moon, it seems that, by the time they became part of the Persian empire in the late sixth century BCE, they were confident enough of the lunar cycle to draw up calendars well into the future. Around this time, the first day of the month may have been aligned to the time when the sun and the moon are in the same part of the sky – what we call “new moon” – rather than when the moon was far enough away from the sun, as viewed from earth, to be able to see it. On the fifteenth day of each month, at full moon, there was a day of rest, called Shabattu, from two Sumerian words meaning “mid-rest”. Although later Shabattu came to be associated with the festival of the full moon in its Babylonian homeland, I find it interesting that the word is the most likely origin for the Hebrew word Shabbat, and hence our day Sabbath, meaning a day of rest.
The Jewish calendar is not the only one to have been influenced by the Babylonians. When the Persian Empire conquered Babylon in the sixth century BCE, it wasn’t long before they adopted this way of measuring time. And after Alexander’s brief empire fragmented, the Seleucids began to use the Persian calendar, and later still the Parthians also adopted it. The various Zoroastrian calendars still in use today were also influenced by the ancient Persian way of reckoning months and years. Many other yearly timetables, more short-lived or more extensively modified, also carried indications of the Babylonian way of reckoning time. To this day, the number of hours in a day (six two-hour periods of daytime, and six of night-time, in ancient times), the number of minutes in an hour, and the number of seconds in a minute, derive from Babylonian timekeeping.
So many people, so many peoples, throughout time and space, all linked by a system at least four thousand years old. We humans are short-lived, ephemeral creatures, but cycles of day and night, lunar phases, yearly seasons, are not. And by watching the moon, we become part of a community that has its own immortality.