Gregorian calendar
The Gregorian calendar, also called the Western calendar and the Christian calendar, is internationally the most widely used civil calendar. It is named for Pope Gregory XIII, who introduced it in 158...
Cash-Strapped Saudi Arabia Switches To Gregorian Calendar To Pay Civil Servants Less
Saudi Arabian civil servants will lose 11 days of pay after the country switched to the Gregorian calendar, the predominant format for organizing time in the West. The switch is part of austerity meas...
The Surprising History Behind Leap Year
The ancient Egyptians did it, and so do we. Here's how a leap day—which occurs Februrary 29—helps keep our calendars and societies in sync. For centuries, trying to sync calendars with the length of t...
Coptic calendar
The Coptic calendar, also called the Alexandrian calendar, is used by the Coptic Orthodox Church and still used in Egypt. This calendar is based on the ancient Egyptian calendar. To avoid the calendar...
Ethiopian calendar
The Ethiopian calendar (Amharic: የኢትዮጵያ ዘመን አቆጣጠር; yä'Ityoṗṗya zämän aḳoṭaṭär) is the principal calendar used in Ethiopia and also serves as the liturgical calendar for Christians in Eritrea and E...
Anno Domini
Anno Domini (AD or A.D.) and Before Christ (BC or B.C.) are designations used to label or number years used with the Julian and Gregorian calendars. The term Anno Domini is Medieval Latin, translated ...
Ole Rømer
Ole Christensen Rømer ([o(ː)lə ˈʁœːˀmɐ]; 25 September 1644, Århus – 19 September 1710, Copenhagen) was a Danish astronomer who in 1676 made the first quantitative measurements of the speed of light. I...
Arabic names of calendar months
The Arabic names of calendar months of the Gregorian calendar are usually phonetic Arabic pronunciations of the corresponding month names used in European languages. An exception is the Aramaic calend...
Common year starting on Wednesday
This is the calendar for any common year starting on Wednesday, January 1 (dominical letter E). Examples: Gregorian years 1975, 1986, 1997, 2003, 2014, 2025 and 2031or Julian year 1903 (see bottom ta...
Fasli Calendar
Fasli Calendar or Fasli era, Fasli (Urdu: فسلى‎, Arabic: فصلى‎) and (English: meaning Harvest) it is an Arabic word Imported to Urdu language.Fasli year means period of 12 months ...
Common year starting on Sunday
A common year starting on Sunday is any non-leap year (i.e., a year with 365 days) that begins on a Sunday, January 1 (dominical letter A) or for any year in which "Doomsday" is Tuesday. Examples: Gre...
Leap year starting on Saturday
This is the calendar for any leap year starting on Saturday, January 1 (except for the leap year 1752 in the Gregorian calendar in which some days of September were removed) (dominical letter BA), suc...
Leap year starting on Friday
This is the calendar for any leap year starting on Friday, January 1 (dominical letter CB), such as 1932, 1960, 1988, 2016, 2044 or 2072.
Leap year starting on Monday
This is the calendar for any leap year starting on Monday, January 1 (dominical letter GF), such as 1940, 1968, 1996, 2024, and 2052.
Common year starting on Saturday
This is the calendar for any common year starting on Saturday, January 1 (dominical letter B). Examples: Gregorian years 1983, 1994, 2005, 2011, 2022 and 2033or Julian years 1905 and 1911 (see bottom...
Determination of the day of the week
There are various methods to calculate the day of the week for any particular date in the past or future. These methods ultimately rely on algorithms to determine the day of the week for any given dat...
French Republican Calendar
The French Republican Calendar (French: calendrier républicain français) or French Revolutionary Calendar (calendrier révolutionnaire français) was a calendar created and implemented during the Fr...
Leap year starting on Thursday
This is the calendar for any leap year starting on Thursday, January 1 (dominical letter DC), such as 1948, 1976, 2004, 2032 or 2060.For this kind of year, the corresponding ISO year has 53 weeks, and...
Millennium
A millennium (plural millennia) is a period of time equal to 1000 years. It derives from the Latin mille, thousand, and annus, year. It is often, but not necessarily, related to a particular dating sy...
Babylonian calendar
The Babylonian calendar was a lunisolar calendar with years consisting of 12 lunar months, each beginning when a new crescent moon was first sighted low on the western horizon at sunset, plus an inter...
Leap year starting on Tuesday
This is the calendar for any leap year starting on Tuesday, January 1 (dominical letter FE), such as 1952, 1980, 2008, 2036 or 2064.
Common year starting on Monday
This is the calendar for any common year starting on Monday, January 1 (dominical letter G). Examples: Gregorian years 1973, 1979, 1990, 2001, 2007, 2018, 2029 and 2035or Julian year 1918 (see bottom...
Leap year starting on Sunday
This is the calendar for any leap year starting on Sunday, January 1 (dominical letter AG), such as 1956, 1984, 2012, 2040, or 2068.This is the only leap year with three occurrences of Friday the 13th...
Common year starting on Thursday
This is the calendar for any common year starting on Thursday, January 1 (dominical letter D). Examples: Gregorian years 1981, 1987, 1998, 2009, 2015, 2026 and 2037 or Julian year 1915 (see bottom ta...
Seven-day week
The seven-day week is used by the majority of the world and is the international standard as specified in ISO 8601.
The seven-day time unit is named in many languages by a word derived from "seven...
Astronomical year numbering
Astronomical year numbering is based on AD/CE year numbering, but follows normal decimal integer numbering more strictly. Thus, it has a year 0, the years before that are designated with negative numb...
Zeller's congruence
Zeller's congruence is an algorithm devised by Christian Zeller to calculate the day of the week for any Julian or Gregorian calendar date. It can be considered to be based on the conversion between J...
Century leap year
In the Gregorian calendar, an end-of-century leap year (often referred to as a century leap year) is a year that is exactly divisible by 400 and, as with every other leap year, qualifies for the inter...
Proleptic Gregorian calendar
The proleptic Gregorian calendar is produced by extending the Gregorian calendar backward to dates preceding its official introduction in 1582.
The proleptic Gregorian calendar is explicitly requi...