Common era

Common Era or Current Era, abbreviated CE, is a calendar era that is often used as an alternative naming of the Anno Domini era ("in the year of the Lord"), abbreviated AD. The system uses BCE as an abbreviation for "before the Common (or Current) Era" and CE as an abbreviation for "Common Era". The CE/BCE designation uses the same numeric values as the Anno Domini year-numbering system first used by the 6th-century Christian monk Dionysius Exiguus. Neither notation includes a year zero, and the two notations (CE/BCE and AD/BC) are numerically equivalent; thus "2017 CE" corresponds to "AD 2017", and "400 BCE" corresponds to "400 BC". The Gregorian calendar and the year-numbering system associated with it is the calendar system with most widespread use in the world today. For decades, it has been the global standard, recognized by international institutions such as the United Nations and the Universal Postal Union.

The expression "Common Era" can be found as early as 1708 in English, and traced back to Latin usage among European Christians to 1615, as vulgaris aerae, and to 1635 in English as Vulgar Era. At those times, the expressions were all used interchangeably with "Christian Era".

Use of the CE abbreviation was introduced by Jewish academics in the mid-19th century. Since the later 20th century, use of CE and BCE has been popularized in academic and scientific publications and more generally by authors and publishers wishing to emphasize secularism or sensitivity to non-Christians, because it does not explicitly make use of religious titles for Jesus, such as "Christ" and Dominus ("Lord"), which are used in the BC/AD notation, nor does it give implicit expression to the Christian creed that Jesus is the Christ.

The year numbering system used with Common Era notation was devised by the Christian monk Dionysius Exiguus in the year 525 to replace the Era of Martyrs system, because he did not wish to continue the memory of a tyrant who persecuted Christians. He attempted to number years from an initial epoch, an event he referred to as the Incarnation of Jesus.

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