Gregorian calendar

Table of Contents

Introduction & Top Questions References & Edit History Quick Facts & Related Topics

Images & Videos

Gregorian calendar

What is Leap Day?

Read Next

Cathedrale St.Jean in Lyon, France has a 14th-century astronomical clock that shows religious feast days till the year 2019; Perpetual Calendar

Ten Days That Vanished: The Switch to the Gregorian Calendar

Calendar showing the month of February

Why Are There Only 28 Days in February?

Ancient Mayan Calendar

Our Days Are Numbered: 7 Crazy Facts About Calendars

February 29, leap day, leap year, happens every four years

Leap Day, February 29

Calendar marking march 15th

22 Questions About Time and Timekeeping Answered

Discover

Young boys working in a thread spinning mill in Macon, Georgia, 1909. Boys are so small they have to climb onto the spinning frame to reach and fix broken threads and put back empty bobbins. Child labor. Industrial revolution

The Rise of the Machines: Pros and Cons of the Industrial Revolution

Leonardo da Vinci (1452-1519), Italian Renaissance painter from Florence. Engraving by Cosomo Colombini (d. 1812) after a Leonardo self portrait. Ca. 1500.

10 Famous Artworks by Leonardo da Vinci

Chapter 4 pg 42 - Chapter header of The Adventures of Tom Sawyer by Mark Twain. Published in 1884 by The American Publishing Company

Periods of American Literature

Shadow of a man holding large knife in his hand inside of some dark, spooky buiding

7 of History's Most Notorious Serial Killers

Calendar showing the month of February

Why Are There Only 28 Days in February?

Abstract vector hi speed internet technology background

History of Technology Timeline

Groups of depositors in front of the closed American Union Bank, New York City. April 26, 1932. Great Depression run on bank crowd

Causes of the Great Depression

Gregorian calendar: References & Edit History

More Articles On This Topic

Assorted References

major treatment
- In calendar: The Gregorian calendar
adoption by United Kingdom
- In United Kingdom: Domestic reforms
insertion of leap year
- In leap year
promulgation by Gregory XIII
- In Gregory XIII
reform of Julian calendar
- In Julian calendar
- In time: Time units and calendar divisions
solar calendar
- In solar calendar
tabulation of year
- In year

Article Contributors

Primary Contributors

The Editors of Encyclopaedia Britannica

Other Encyclopedia Britannica Contributors

Article History

Type	Description	Contributor	Date
	Add new Web site: History Today - The Gregorian Calendar Adopted in England.	Yamini Chauhan	Dec 19, 2024
	Add new Web site: Johns Hopkins University Applied Physics Laboratory - The 400th Anniversary of the Gregorian Calendar.	Grace Young	Oct 23, 2024
	Add new Web site: Live Science - The Gregorian calendar: Why we have Leap years and April Fools' Day.	Gloria Lotha	Jun 18, 2024
	Add new Web site: Academia - The Imposing of the Gregorian Calendar and its Impact on Levantine Christians: Local Dynamics and Foreign Interferences (1858-1864).	Gloria Lotha	Mar 05, 2024
	Media added.	Meg Matthias	Jan 26, 2024
	Add new Web site: Connecticut State Library - Calendars.	Gloria Lotha	Oct 18, 2023
	Add new Web site: Ancient Origins - New Year, Old Calendar: The Origins and Controversy of the Gregorian Calendar.	Gloria Lotha	Jun 20, 2023
	Article revised and updated.	Erik Gregersen	Apr 19, 2021
	Top Questions updated.	The Editors of Encyclopaedia Britannica	Sep 25, 2020
	Add new Web site: ThoughtCo. - Gregorian Calendar.	Aakanksha Gaur	May 11, 2018
	Add new Web site: Encyclopedia Virginia - The Gregorian Calendar.	Aakanksha Gaur	Apr 13, 2018
	Media added.	Amy Tikkanen	May 04, 2010
	Added new Web site: The Galileo Project - The Gregorian Calendar.	Kanchan Gupta	Jan 03, 2008
	Article revised and updated.	William L. Hosch	Jun 15, 2006
	Article added to new online database.	The Editors of Encyclopaedia Britannica	Jul 20, 1998