Epoch

Calendar eras

Pre-modern eras

• The Yoruba calendar uses 8042 BC as the epoch, regarded as the year of the creation of Ile-Ife by the god Obatala, also regarded as the creation of the earth.
• Anno Mundi is used in
• * the Byzantine calendar.
• * the Hebrew calendar.
• The Mesoamerican Long Count Calendar uses the creation of the fourth world in 3114 BC.
• Olympiads, the ancient Greek era of four-year periods between Olympic Games, beginning in 776 BC.
• Ab urbe condita, used to some extent by Roman calendars of the Roman imperial period.
• Buddhist calendars tend to use the epoch of 544 BC.
• The term Hindu calendar may refer to a number of traditional Indian calendars. A notable example of a Hindu epoch is the Vikram Samvat, also used in modern times as the national calendars of Nepal and Bangladesh.
• The Julian and Gregorian calendars use as epoch the Incarnation of Jesus as calculated in the 6th century by Dionysius Exiguus. This epoch was applied retrospectively to the Julian calendar, long after its original creation by Julius Caesar.
• The epoch of the Islamic calendar is the Hijra. The year count in this calendar shifts relative to the solar year count, as the calendar is purely lunar: its year consists of 12 lunations and is thus ten or eleven days shorter than a solar year. This calendar denotes "lunar years" as Anno Hegiræ or AH. This calendar is used in Sunni Islam and related sects.
• The epoch of the official Iranian calendar is also the Hijra, but it is a solar calendar; each year begins at the Northern spring equinox. This calendar is used in Shia Islam and related sects.

  Modern eras

• The Bahá'í calendar is dated from the vernal equinox of the year the Báb proclaimed his religion. Years are grouped in Váḥids of 19 years, and Kull-i-Shay of 361 years.
• In Thailand in 1888 King Chulalongkorn decreed a National Thai Era dating from the founding of Bangkok on April 6, 1782. In 1912, New Year's Day was shifted to April 1. In 1941, Prime Minister Phibunsongkhram decided to count the years since 543 BC. This is the Thai solar calendar using the Thai Buddhist Era. Except for this era, it is the Gregorian calendar.
• In the French Republican Calendar, a calendar used by the French government for about twelve years from late 1793, the epoch was the beginning of the "Republican Era", September 22, 1792.
• The Indian national calendar, introduced in 1957, follows the Saka era.
• The Minguo calendar used by officials of Taiwan and its predecessor dates from January 1, 1912, the first year after the Xinhai Revolution, which overthrew the Qing Empire.
• North Korea used a system that starts in 1912, the year of the birth of its founder Kim Il-Sung until 2024.
• The Fascist Era dates to Mussolini's March on Rome in 1922, and was in use only in countries under hegemony of the Fascist regime of Benito Mussolini. It has been defunct since the fall of the Italian Social Republic in 1945.
• In the scientific Before Present system of numbering years for purposes of radiocarbon dating, the reference date is January 1, 1950.
• Different branches of Freemasonry have selected different years to date their documents according to a Masonic era, such as the Anno Lucis.
• The Holocene calendar uses 10,000 BC as the epoch, a rough approximation of the beginning of the Holocene epoch on the geological time scale.

  Regnal eras

Fictional eras

• Events in the Star Wars universe are conventionally dated using an epoch of the Battle of Yavin.
• Events in the Avatar: The Last Airbender universe are conventionally dated using an epoch of the genocide of the air nomads.