What Julio Cesar, the famous Roman general and dictator, has to do with the leap year? And what is a leap year?
Leap year is the year made up of 366 days, with the month of February having 29 days, and not 28 as in other years. The other years are each 365 days, 5 hours, 48 minutes and 46 seconds. It is this difference of more than five hours that leads us to adopt the leap year.
But a difference from what? The calendar is a form of timekeeping created by humans. The reference for creating a calendar are the movements of celestial objects such as the moon and the sun. the time that the Earth it takes to go around the sun is called a year. But from the above, a year does not have 365 exact days, as the Earth's movement around the Sun takes a little longer to occur.
It was to try to resolve this gap that Julius Caesar, in 46 a. C., asked the astronomer Sosigenes of Alexandria guide him in reforming the calendar in force in Rome. Legend said that the Roman calendar had been created by the city's founder, Romulus. This first calendar had 304 days, divided into 10 months, with 6 of 30 days and 4 of 31 days. But, as we have seen, this count did not match the time it takes the Earth to make a complete circle around the Sun.
Rômulo's successor, Numa Pompílio, sought to solve this problem by including more two months, one with 29 days and the other with 28 days, and one day of each of the other months would be taken out. As a result, the year in this calendar now has 355 days. To resolve the difference between the calendar count and the Earth's movement, every two years another month was added.
But the calendar was not followed correctly. As time went on, the difference between the Earth's motion and the calendar's count only increased. At the time of Julius Caesar, the difference was up to 80 days!
Julius Caesar's solution was profound. Inspired by the Egyptian solar calendar, Sosigenes of Alexandria proposed that the calendar should have 365 days and every four years a new day was added to be able to bridge the difference between the time of the Earth's movement and that of the calendar. That day was the leap day.
The leap name comes from the form of counting the month among the Romans. The month was divided into three parts: the calendas were the first days; the ninths, the intermediate days; and the gone, the final days. The added day was the bis sextus ante kalendas martias, in Latin. It was the repetition of the sixth day before the March calendas, as the Romans counted the days backwards. This is the origin of the name.
Resolved to adopt the new calendar, Julius Caesar still needed to overcome the 80-day lag. For this, he decided that the year 46 a. Ç. it would have 445 days, with the counting of time coming on track for the following year. For being a year with so many days, he became known as the Year of Confusion.
As Obelix, a character in the Asterix comic book, said: "They're crazy, those Romans!"
The new calendar was renamed Julian calendar, in honor of Julius Caesar. He gained a month after death for himself: the month of July. Emperor Octavius Augustus also wanted to have a month, and the eighth month of the year was renamed August. One day of February was also removed so that the months of July and August had the same number of days.
The Julian calendar was in effect in the Western European world until the 16th century, when the lag of days was big again: 11 days. A new reform of the calendar was needed and it was ordered by Pope Gregory VIII. Hence the name of Gregorian calendar given to the calendar we use today.
By Tales Pinto
Master in History