Roman calendar dating
March, the first month of the year in the old Roman calendar, was in honor of the god of war Mars.While the origin of the word April (Aprilis in Latin) is unclear, some historians believe that it comes from the Etruscan word Apru meaning the goddess Aphrodite, thereby celebrating the goddess Venus (the Roman equivalent of Aphrodite) the goddess of love and fertility.This system of synchronization was far from perfect and Julius Caesar (100 BCΕ – 44 BCΕ) introduced the Julian calendar in 46 B. which consisted of 365 days and now started on January 1st. D.) added a leap day to the month of February making the average length of the year 365.25 days.
So, the Julian calendar many countries felt wasn't a true year so they made the change.
The Gregorian calendar was able to make up for this 11 minute difference by not making years divisible by 100 to be a leap year.
The solution was to remove the leap day to years evenly divisible by 100 but not evenly divisible by 400.
For example, the year 1900 is evenly divisible by 100 (1900/100=19) but not by 400 (1900/400=4,75), therefore the month of February in the year 1900 has 28 days.
This means that the year 2,100, for example wouldn't be a leap year whereas in the Julian calendar format - it would be.