The Gregorian calendar is a just minor correction to the Julian. In the Julian calendar every fourth year is a leap year in which February has 29, not 28 days, but in the Gregorian, with the introduction of the “Leap Year Rule”, it was established that “years divisible by 100 are not leap years unless they are also divisible by 400″. Therefore, the years 1600, 2000, and 2400 are leap years, while 1700, 1800, 1900, 2100, 2200, and 2300 are not leap years. In other words: three LEAP years are eliminated every 400 years to keep the calendar on track.
The Ancient Maya count is an uninterrupted count of days based on the advanced vigesimal mathematical system known as the Long Count. This count of days starts on August 11, -3113, on Long Count marker 0.0.0.0.0. 4Ajaw — 8Cumku. This count is independent of the Gregorian calendar and keeps running in parallel to include the Leap Day anomaly.