The Gregorian calendar is the solar calendar for counting the years, months, weeks and days and based on the seasons of the year.
The Gregorian calendar is a calendar created in Europe in 1582 at the initiative of Pope Gregory XIII.
The Gregorian calendar was created with the aim of correcting the errors of the previous calendar: the Julian calendar. The Gregorian calendar is the most used calendar in the world today.
Although not considered a perfect calendar, it is more accurate than its predecessor, the Julian calendar.
Some defects of the Gregorian calendar are: the irregularity of the duration of the months (between 28 and 31 days), the relationship between the date and the day of the week, and the mobility of Christian dates, such as Easter.
A calendar is a time measurement system that groups and counts days, dividing them into months and years.
As for etymology, the word calendar comes from the Latin calendar, which means book of calendars. This was the book used to count the days of the religious festivals marked at the beginning of each lunar month in Ancient Rome, before the introduction of the Julian calendar.
The calendar is called Gregorian after Pope Gregory XIII, its creator.
How does the Gregorian calendar work?
According to the Gregorian calendar, the year consists of 12 months that can be between 28 and 31 days. A year can have 365 or 366 days, in which case it is called a leap year.
January - 31 days
February - 28 or 29 days
March - 31 days
April - 30 days
May - 31 days
June - 30 days
July - 31 days
August - 31 days
September - 30 days
October - 31 days
November - 30 days
December - 31 days
The month of February is sometimes 28 days, and sometimes 29 days, depending on whether the year is a leap year or not.
Leap years occur every four years and have 366 days, that is, one day more than regular years, with 365 days. This extra day is February 29th.
The implementation of the Gregorian calendar allowed the adjustment of the calendar with astronomical events such as the spring equinox and winter solstice.
Origin of the Gregorian Calendar
Before the Gregorian calendar was created, the Julian calendar was in effect, which was late. Therefore, Passover was later than the spring equinox. Calendar reform was discussed at the Council of Constance and later at the Council of Trent.
The Gregorian calendar was implemented in 1582 in Italy, Poland, Portugal and Spain. Though implemented by Pope Gregory XIII, the calendar reforms were created by Italian astronomer and philosopher Luigi Giglio.
Gregorian calendar and Julian calendar
The Gregorian calendar replaced the Julian calendar. The latter was instituted by the Roman dictator Julius Caesar, but it contained some inaccuracies. He did not contemplate the Earth's translation movement, that is, the time it takes the Earth to circle around the Sun.
The formula used to calculate leap years was changed with the Gregorian calendar. Therefore, when this was implemented, 10 days were excluded from the calendar to readjust the inaccuracies created by the Julian calendar. Thus, in 1582 the 4th of October was changed to 15th of October.
See more about the meaning of leap year.