It is the end of 2021, and what better time to wonder: where do our dates even come from? Well, much of the system we use today revolves around calendars created by the Romans.
The early Roman calendar
Beginning in March and ending in December, this dating system consisted of 10 months, totaling 304 days. The months went in the following:
Romulus is said to have created the first calendar. However, Numa Pompilius, the second king of Rome, supposedly added January and February to increase the count by 50 days. He then took a day from each of the 30 day months and divided them between the two new months, leaving 56 new days. Pompilius gave January an extra month (out of superstition of even numbers), but left February at 28 days. In the end, this calendar contained 12 months of 355 days.
With this, the fifth king of Rome Lucius Tarquinius Priscus fully employed this calendar. To prevent it from falling out of line with the seasons, he used an intercalation month Mercedonius between February 23rd and 24th once every two years. On top of this, the last five days of the month were not counted. In turn, this calendar had an average of 366.25 days per year.
The Julian calendar
When the Roman republic was founded years later, Emporer Julius Caesar formed what is now known as the Julian calendar. Advised by Sosigenes (a Greek astronomer), Caesar created a calendar of 365.25 days and 12 months of 30 and 31 days each. Because the dated calendar fell out of line with the solar calendar, Caesar aimed to readjust the dates to align with the seasons. To achieve this, he made the year 46 BCE have 455 days. This begins to seem more similar to the Gregorian calendar we use today, a modified system of the Julian calendar. As of now, the total difference between the two calendars is just 13 days (yet it is growing larger)!
Citations
https://www.britannica.com/science/calendar/The-early-Roman-calendar
https://www.tondering.dk/claus/cal/roman.php
https://www.britannica.com/science/Julian-calendar
http://roma.andreapollett.com/S7/roma-cal.htm (Image)