<P> The Gregorian calendar is the most widely used calendar in the world today . For decades, it has been the unofficial global standard, adopted in the pragmatic interests of international communication, transportation, and commercial integration, and recognized by international institutions such as the United Nations . </P> <P> Traditionally, English followed Latin usage by placing the "AD" abbreviation before the year number . However, BC is placed after the year number (for example: AD 2017, but 68 BC), which also preserves syntactic order . The abbreviation is also widely used after the number of a century or millennium, as in "fourth century AD" or "second millennium AD" (although conservative usage formerly rejected such expressions). Because BC is the English abbreviation for Before Christ, it is sometimes incorrectly concluded that AD means After Death, i.e., after the death of Jesus . However, this would mean that the approximate 33 years commonly associated with the life of Jesus would not be included in either of the BC and the AD time scales . </P> <P> Terminology that is viewed by some as being more neutral and inclusive of non-Christian people is to call this the Current or Common Era (abbreviated as CE), with the preceding years referred to as Before the Common or Current Era (BCE). Astronomical year numbering and ISO 8601 avoid words or abbreviations related to Christianity, but use the same numbers for AD years . </P> <P> The Anno Domini dating system was devised in 525 by Dionysius Exiguus to enumerate the years in his Easter table . His system was to replace the Diocletian era that had been used in an old Easter table because he did not wish to continue the memory of a tyrant who persecuted Christians . The last year of the old table, Diocletian 247, was immediately followed by the first year of his table, AD 532 . When he devised his table, Julian calendar years were identified by naming the consuls who held office that year--he himself stated that the "present year" was "the consulship of Probus Junior", which was 525 years "since the incarnation of our Lord Jesus Christ". Thus Dionysius implied that Jesus' Incarnation occurred 525 years earlier, without stating the specific year during which his birth or conception occurred . "However, nowhere in his exposition of his table does Dionysius relate his epoch to any other dating system, whether consulate, Olympiad, year of the world, or regnal year of Augustus; much less does he explain or justify the underlying date ." </P>

When did ad in other words anno domini begin