A calendar is a system of organizing days for social, religious, commercial, or administrative purposes. The Gregorian calendar is the most widely used calendar in the world today. It is a solar calendar, meaning that it is based on the Earth’s orbit around the sun. The Gregorian calendar has 12 months, each with a different number of days. November has 30 days, December has 31 days, and January has 31 days.
The Gregorian calendar was introduced in 1582 by Pope Gregory XIII. It was a modification of the Julian calendar, which had been in use since 46 BC. The Julian calendar had a leap year every four years, but this caused the calendar to drift out of sync with the Earth’s orbit around the sun. The Gregorian calendar corrected this error by introducing a more complex leap year rule. The Gregorian calendar is now used in most countries around the world.
