The Gregorian calendar, which is probably the most broadly used calendar on the planet right now, operates on a cycle of 400 years. Which means that the calendar repeats itself each 400 years. Because of this, the 12 months 2025 would be the identical because the 12 months 2425, 2825, and so forth.
The Gregorian calendar was launched in 1582 by Pope Gregory XIII. It was a modification of the Julian calendar, which had been in use since 45 BC. The Julian calendar had a bissextile year each 4 years, however this induced the calendar to float out of sync with the photo voltaic 12 months. The Gregorian calendar launched a brand new rule for leap years: a 12 months is a bissextile year whether it is divisible by 4, however not by 100, except it is usually divisible by 400. This rule ensures that the Gregorian calendar stays in sync with the photo voltaic 12 months.
