The Monk's Guess
I often wonder when the calendar year we use became universally accepted. It certainly wasn’t 10 A.D., because Rome had its own system. A person living in 124 B.C. using the Common Era calendar is even more absurd. Such an individual would have to be prescient of the arrival of Jesus Christ, a figure so central to civilization that the date of his birth was to become the anchor to our modern measure of time.
The continuous flow of time extending to infinity (or to the extinguishment of humans, whichever comes first) is a modern concept. In previous eras, the year was identified using shorter timeframes. In Assyria, the Akitu festival, which took place at the beginning of each Assyrian year, would select by lot a person’s name. This person would then be called the limmu, or the name of the year. So a year was designated by the name of a specific person rather than a sequential number. To translate such dates to our calendar, historians use astronomical events, such as recorded eclipses, to anchor these named years into our system.
Ancient Greece used the Olympics as its date anchor. Beginning in 776 B.C., the first Olympiad was held. Subsequently, every four years, like today, another Olympiad would take place. To create a date, the number of the Olympiad and the year within a specific cycle were noted. For example, the first year of the first Olympiad would be 1,1; the third year of that Olympiad would be 1,3. Following this logic, the year 314 B.C. would be written by the ancient Greeks as 116,3.
So how did our calendar year start? Was there a transformation of human cognition of eternity that required numbers extending out indefinitely? Hardly. Like most things in our civilization, a practical problem brought our A.D./B.C. mindset to fruition: calculating Easter’s date.
Easter is defined as the first Sunday after the first ecclesiastical full moon that occurs on or after the vernal equinox. (No wonder the day Easter falls on is always a surprise to me!) To calculate years in advance, the solar year and lunar phases must be aligned, an arduous task that for centuries used Diocletian’s first year of rule as the anchor point. Dionysius Exiguus, a Scythian monk, thought this was a bad idea, since Diocletian was not a friend of the church, to put it mildly. Instead, he used Jesus Christ’s birth as the new anchor point. Upon designing the new system, he placed Jesus’s birth 532 years earlier based on his reading of the Bible.
So the calendar system the whole world uses is based on a monk’s guess as to when Jesus was born. Later on, historians, again using astronomical records, deduced that Jesus was born in the window of 7 B.C. to 4 B.C. In addition, because at the time of this invention there was no concept of zero, there is no year denoted by zero, whether 0 B.C. or 0 A.D. Therefore, December 31, 1 B.C. is the night before January 1, 1 A.D. It wasn’t until about a thousand years later, in 1627, that Denis Pétau published his exhaustive masterwork on chronography, De doctrina temporum. It is here that the nomenclatures AD/BC were popularized in this highly influential work. It became a convention where AD was placed before the year (Anno Domini) and BC placed afterward, although nowadays A.D. is placed after the date.
This dating system did not become widely used for a long time. Each civilization had its own chronology. Tenth-century Byzantium used the beginning of the world, September 1, 5509 B.C., as the start of its calendar. So the year for June 15, 1103 A.D. would be 6611 AM in their world. The Muslim world also had its own calendar anchored on the Hijra of the Prophet Muhammad from Mecca to Medina. It wasn’t until 1949, with the People’s Republic of China adopting the Common Era calendar, that the world was completely synced to the same calendar year.
Perhaps this evolution of our calendar system fascinates me because my own fiction deals with the impossibly faraway horizon of eternity. As human beings, we don’t spend much time contemplating the unending flow of time. Historically, civilizations revealed this bias by anchoring years to the reigns of monarchs or, like the ancient Greeks, tethering their timekeeping to their Olympic Games. It simply wasn’t instinctual to create a timeline extending forever, an abstraction far beyond human comprehension. But because the rules for calculating Easter were so arcane, we wound up constructing an accidental runway to infinity: an unbroken path that silently outlasts the empires and the fragile lives that built it.
