Roman dating essentials

Julius Caesar (He's the one on the plinth.)

Julius Caesar (He’s the one on the plinth.)

Watching the countdown calendar to the publication day of INCEPTIO on 1 March reminded that the first of the month in the Roman system – the Kalends  – ended up as our word for measuring the whole thing.

In my Roma Nova thrillers, I use the standard Western system the world has agreed to use, but how did the traditional Roman system work? And were the Roma Novans right to abandon it?

According to legend, Romulus, the founder of Rome, instituted the calendar in about 738 BC. But it probably evolved from the Greek lunar calendar, which in turn was derived from the Babylonian (Nothing new under the sun, or the moon, then).

Originally, the Roman calendar appears to have consisted only of 10 months and of a year of 304 days. The remaining 61¼ days were apparently ignored, resulting in a gap during the winter season. Awkward. The months bore the names Martius, Aprilis, Maius, Junius, Quintilis (renamed later as Iulius), Sextilis (ditto Augustus), September, October, November, and December – the last six original names corresponding to the Latin words for 5 to 10. The early Roman king Numa Pompilius is credited with adding January at the beginning and February at the end of the calendar to create the 12-month year. In 452 BC, February was moved between January and March.

By the 1st century BC, the Roman calendar had become hopelessly confused. The year, based on cycles and phases of the moon, totaled 355 days, about 10¼ days shorter than the solar year. The occasional intercalation of an extra month of 27 or 28 days, called Mercedonius, kept the calendar in step with the seasons.

Of course, there was a political dimension – this was Rome. The Pontifex Maximus and the College of Pontiffs – the religious leaders who exercised strong influence in a society thriving on superstition – had the authority to alter the calendar. If they wanted to reduce or extend the term of a particular magistrate or other public official they just changed the calendar. Brilliant trick. One that today’s leaders would love to have in their frog boxes.

Finally, in 46 BC, Julius Caesar intervened and initiated a thorough reform that resulted in a more consistent dating system, the Julian calendar. It was only superseded by the Gregorian calendar in 1582, although it continued to be used as the civil calendar in some countries into the 20th century.

Knowing what day of the month it was
Roman months were based on a series of markers. The first day of the month was called the Kalends, but the date of the other markers varied according to month length. Roughly, the next marker, the Nones, was around the 5th, sometimes 7th, of the month with the infamous Ides halfway through the month, somewhere around 13th to 15th. To get to the end of the month from the Ides, you counted backwards from the next month’s Kalends (1st). Dont let’s go anywhere leap years and dating of equinoxes!

consul-listThe principal method that the Romans used to identify a year for dating purposes was to name it after the two consuls who took office in it – hence the consular year. In and after 309 AD there were years when no consuls were appointed and the consular date was given a count of years since the last consul. This threw the dating system out which must have caused havoc for trade, politics and the law, let alone normal people’s lives. The system of consular dating, obsolete since at least 537 AD, was formally abolished in the law code of Byzantine emperor Leo VI, issued in 888, probably to the relief of all concerned.

Now, given the mental acrobatics of working out where you were in the month, then trying to remember the date of who was consul when, remind me why the Roma Novans opted to abandon the traditional dating systems?


Updated December 2018: Alison Morton is the author of Roma Nova thrillers –  INCEPTIO,  PERFIDITAS,  SUCCESSIO,  AURELIA,  INSURRECTIO  and RETALIO.  CARINA, a novella, and ROMA NOVA EXTRA, a collection of short stories, are now available.  Audiobooks are available for the first four of the series.

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