The year 46 BCE, weighing in at 445 days!
Ancient Rome made some very important contributions to the calendar as we know it now. Thankfully, not all of their contributions stuck around. From having a monthless period over winter, to an unpredictable leap month named Mercedonius, many of their changes left their citizens quite confused. Perhaps the oddest temporary change was the 445-day year, which took place in 46 BCE.
Despite the way it may seem, in the long run, this very long year actually fixed more confusion than it caused. Before then, the calendar year took place several months before the seasonal year.
What was wrong with the previous calendar?
Before 46 BCE, the Roman calendar was an unnatural mix of the solar and lunar cycles. Every month corresponded to one cycle of the moon, but 12 lunar cycles amount to less than a 365-day year.
To accommodate the shorter year while still tracking lunar cycles, the Romans would insert an intercalary (leap) month, which they called Mercedonius that was inserted after February when needed. Unlike leap days, Mercedonius was not on a set schedule, and its existence (or lack thereof) was determined each year by the Pontifex Maximus, a Roman high priest. Since no one knew if this month would occur, making long term plans was incredibly confusing.
How in the world was the calendar 80 days off?
There are two main answers to this question: Firstly, the current Pontifex Maximus had been pretty busy, to say the least,
…the current Pontifex Maximus happened to be Julius Caesar itself. And, as we know, the triumphant dictator of Rome spent the last 15 year far away campaigning, fighting and plotting. As a consequence, the Roman calendar was 3 months out of sync.
Aside from Caesar’s busy itinerary, the second significant reason why the calendar didn’t work was politics. The Pontifices (my new favourite word, by the way) Maximus were more politically affiliated in these later years. With the ability to change the lengths of politicians’ terms by a month, their power was abused quite often.
After spending time in Egypt and seeing their less confusing calendar, Caesar decided enough was enough. He gathered the smartest astronomers and mathematicians in Rome and temporarily added three extra months to transition to the Julian calendar, which wasn’t much different than the Gregorian calendar we use today. (it even had a leap day every four years)
So while it may feel like the year is taking eons to pass, be glad you weren’t born a couple of thousand years earlier.