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 was introduced in 1582 by Pope Gregory XIII as a of the Julian calendar, which had been in use since 46 BC.
The Gregorian calendar is a solar calendar, meaning that it is based on the Earth’s orbit around the Sun. The year in the Gregorian calendar is divided into 12 months, each of which has either 30 or 31 days, except for February, which has 28 days (or 29 days in a leap year). The average length of a year in the Gregorian calendar is 365.2425 days.
