Gregorian Calendar

The Gregorian Calendar, named after Pope Gregory XIII, came into being in 1582 to correct errors in the Julian Calendar that became apparent over time. The Julian calendar was actually 10 days ahead of where it should have been, and this was corrected with the new Gregorian Calendar. The Gregorian Calendar is the calendar that is most widely used in the world today. It consists of 365 days in each year, with a 366-day leap year every fourth year. The calendar is broken down into 12 months. The last year of each century (years that end in '00') is not counted as a leap year unless it is divisible by 400.

It is the same as the Julian Calendar, except that the Julian Calendar included the last year of every century as a leap year.