Monday 5 February 2018

mensis intercalaris

Previously we’ve discussed how the sixty days or so that mark the dreariest winter season went by without record until King Numa Pompilius (in the days pre-Republic) instituted calendar-reform measures to augment the fair-weather ten month calendar that the Romans had been using since the city’s founding, recognising that dates were being constantly recalculated as the seasons drifted into one another and that the civic uses of a calendar expanded beyond its agricultural roots, but we didn’t know the whole story nor of their superstitious aversion to round numbers.
Ianuarius and Februarius (from the word februum, a device for ritual purifications and figuratively marked the time when fallow fields were tended to and when olive trees could be pruned) were added as the last months of the year, and to coincide as closely as possible to the passing of the lunar year, they assigned each month either twenty nine or thirty-one days on an alternating basis. To mathematically align with the 355 days of the lunar year and the twelve observed cycles of the Moon, however, one month would have to have an even number of days, so February became the odd one out. The insertion of intercalary time was still necessary to manage the procession of the seasons but instead of a leap-day like we award February with on a regular basis, the Romans adopted an entire leap-month called Mercedinus—“work month”—which should have been used judiciously every other year to keep everything in sync. All time-keeping decisions, however, were invested in the pontifex maximus, and as an active politician usually held this esteemed position it was not unheard of exercising this prerogative as a punitive or prolonging measure to increase or curtail the administration of consul members, at the expense of accuracy in tracking time. When Julius Caesar took power in 46 BC, he decreed that Rome stop this caprice and adopt a solar calendar that is more familiar to the modern civil calendar, based on Western traditions.