En route to founding one of the greatest empires the world has ever seen, the Romans delivered innovations that would survive for centuries.
Advanced architectural methods that enabled them to receive water and construct towering structures such as the Pantheon? Check.
Early forms of books and newspapers that allowed for the widespread sharing of information? Check.
A calendar to match the peculiarities of the all-important solar cycle? Check.
Yes, the modern calendar — shortened February and all — sprung from the efforts of some famed Roman rulers of antiquity. Read on to find out how it came about.
The Original Roman Calendar Ignored the Winter Months
The first organized Roman calendar is said to have originated under the reign of Romulus, some 15 years after Rome's foundation in 753 BCE.
This calendar consisted of 10 months — Martius, Aprilius, Maius, Iunius, Quintilis, Sextilis, September, October, November, and December — with 30 or 31 days each, for a total of 304 days.
This is well short of the established solar year of approximately 365.25 days. However, the Romans tackled that problem by essentially ignoring the 60-plus cold-weather days that were useless for farming purposes, before commencing a new year with the first new moon before the spring equinox.
Rome’s Second King Developed the 12-Month Calendar
The next step in the long march to an accurate Roman calendar arrived with the city's second king, Numa Pompilius.
In an attempt to establish a year based on the 12 lunar cycles, Pompilius tacked on the new months of Ianuarius and Februarius to the end of the calendar. He also tinkered with some of the existing months, as even numbers were considered unlucky, and assigned each one a length of 29 or 31 days.
Of course, 12 months of odd numbers added up to an even number, which meant that one month would have to change to keep the entire year from being unlucky. Likely due to its placement at the end of the calendar, Februarius not only wound up with the even number but became 28 days to make the total year approximately 354 days.
The Month “Mercedonius” Was Added at Inconsistent Intervals
The problem with this calendar was that solar-based seasons and the activities that followed — including planting or harvesting — would continuously slide to different parts of the year.
The Roman solution to this was "intercalation," the addition of yet another month to the calendar every two to three years to keep in line with the solar cycle. Later known as "Mercedonius," this intercalary month was enacted before the usual end of Februarius and pushed the maximum length of the year to 378 days.
This system wasn't exactly accurate, either — the Roman calendar averaged 366 days at this point — but the bigger problem stemmed from the people in charge of enforcing the rules. The Roman high priests, known as pontifices, were the only ones with the authority to mark the start of Mercedonius, and they often did so to lengthen or shorten the administrative terms of political allies and foes.
Julius Caesar Overhauled the Solar Calendar
The Roman calendar received another overhaul after the rise of Julius Caesar, who consulted with top mathematicians and astronomers to clean up the mess left by the centuries-long, haphazard application of Mercedonius.
The result was what became known as the Julian calendar, which did away with the unlucky-number superstition and established the now-accepted lengths of the 12 months.
Februarius, which had moved with Ianuarius to the front of the calendar a few centuries earlier, remained at 28 days. It was also designated as a month of purification ceremonies. However, it was chosen again as a point of intercalation, only this time it was an extra day added every four years to bring the calendar closer to the true cosmic timetable at 365.25 days.
Following a 445-day year to offset the aforementioned mess and reset the seasons, the Julian calendar was implemented for the new year of 45 BCE.
The Gregorian Calendar Remained True to the Julian Predecessor
For all of its carefully calculated changes, the Julian calendar remained problematic for a few more years.
Again, this was a matter of human application, as pontifices counted the leap day — an extra day added to the calendar every four years to ensure the calendar stayed aligned with the Earth’s rotation around the sun — every three years by mistake. Fortunately, Augustus Caesar solved this problem within a few decades by decreeing an end to intercalation until the calendar was up to speed.
One more realignment was instigated in 1582, after the slight drifting of seasons over a millennium and a half required another astronomical tweak and the disappearance of 10 days from the calendar, per decree from Pope Gregory XIII.
While the rest of the world slowly shifted to the Gregorian calendar from that point forward, it remained true to the guidelines shaped over hundreds of years by the Roman timekeepers, and included the unusual designations assigned solely to the lonely month of February.