The presence or absence of year 0 is determined by convention among a group of writers such as historians or astronomers. Neither the calendar (Julian or Gregorian) nor the era (Anno Domini or Common Era) determines that. If writers do not use the convention of their group, they must explicitly state whether or not they include a year 0 in their count of years, otherwise their historical dates will be misunderstood. The Julian calendar was introduced by Julius Caesar in 46 BC, taking force in 45 BC or 709 ab urbe condita. ... The Gregorian calendar is the calendar widely used in the Western world. ... Anno Domini (Latin: In the year of the Lord), or more completely Anno Domini Nostri Iesu Christi (in the year of our Lord Jesus Christ), commonly abbreviated AD or A.D., is the designation used to number years in the dominant Christian Era in the world today. ... The Common Era (CE), also known as the Christian Era and sometimes as the Current Era, is the period beginning with the year 1 onwards. ...

Virtually all modern historians (including Wikipedia) do not include a year 0 when numbering years. Thus 1 BC or 1 BCE immediately precedes AD 1 or 1 CE, regardless of the calendar. Note that the anno Domini method of numbering years was not widely used in Western Europe until the ninth century, and the 1 January to 31 December historical year was not uniform throughout Western Europe until 1752. The terms anno Domini, common era, and vulgar era were used interchangeably between the Renaissance and the nineteenth century, at least in Latin. But vulgar era was suppressed in English at the beginning of the twentieth century after vulgar acquired the meaning of "offensively coarse", replacing its original meaning of "common" or "ordinary". Consequently, historians regard all three eras as equal. Centuries: 2nd century BC - 1st century BC - 1st century Decades: 50s BC 40s BC 30s BC 20s BC 10s BC - 0s BC - 0s 10s 20s 30s 40s 6 BC 5 BC 4 BC 3 BC 2 BC 1 BC 1 2 3 4 Events Births December 25 - Jesus (died about... (Redirected from 1 BCE) Centuries: 2nd century BC - 1st century BC - 1st century Decades: 50s BC 40s BC 30s BC 20s BC 10s BC - 0s BC - 0s 10s 20s 30s 40s 6 BC 5 BC 4 BC 3 BC 2 BC 1 BC 1 2 3 4 Events Births December... Events The first full year in the life of Jesus as assigned by Dionysius Exiguus in his Anno Domini era. ... (Redirected from 1 CE) For other uses, see One (disambiguation), for the number, see Number 1. ... Western Europe is distinguished from Eastern Europe by differences of history and culture rather than by geography. ... (8th century - 9th century - 10th century - other centuries) Events Beowulf might have been written down in this century, though it could also have been in the 8th century Viking attacks on Europe begin Oseberg ship burial The Magyars arrive in what is now Hungary, forcing the Serbs and Bulgars south... January 1 is the first day of the calendar year in both the Julian and Gregorian calendars. ... December 31 is the 365th day of the year (366th in leap years) in the Gregorian Calendar. ... 1752 was a leap year starting on Saturday (see link for calendar). ... By Region: Italian Renaissance Northern Renaissance -French Renaissance -German Renaissance -English Renaissance The Renaissance was an influential cultural movement which brought about a period of scientific revolution and artistic transformation, at the dawn of modern European history. ... Alternative meaning: Nineteenth Century (periodical) (18th century — 19th century — 20th century — more centuries) As a means of recording the passage of time, the 19th century was that century which lasted from 1801-1900 in the sense of the Gregorian calendar. ... Latin is the language originally spoken in the region around Rome called Latium. ... The English language is a West Germanic language that originates in England. ... (19th century - 20th century - 21st century - more centuries) Decades: 1900s 1910s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s The 20th century lasted from 1901 to 2000 in the Gregorian calendar (often from (1900 to 1999 in common usage). ...

However, at least two groups do include a year 0 when they number the years before these eras, astronomers and some Maya historians. In addition, some calendars of South Asia begin their counts of years with a year 0.

Bede

Bede was the first historian to use a BC year and hence the first to adopt the convention of no year 0 between BC and AD, in his Historia ecclesiastica gentis Anglorum (Ecclesiastical history of the English people, 731). Previous Christian histories used anno mundi (in the year of the world"), or anno Adami ("in the year of Adam", beginning five days later, used by Africanus), or anno Abrahami ("in the year of Abraham", beginning 3,412 years later according to the Septuagint, used by Eusebius), all of which assigned "one" to the year beginning at Creation, or the creation of Adam, or the birth of Abraham, respectively. All began with year one because the counting numbers begin with one, not zero. Bede simply continued this earlier tradition relative to the AD era. The inventor of AD, Dionysius Exiguus in 525, did not specify whether he began his count at one or zero (nor did he mention BC). Even though Bede did not begin his count at zero, he was well aware of zero as a number because zero was the first epact of the nineteen-year cycle used to calculate the date of Easter, as he explained in his De temporum ratione (On the reckoning of time, 725). Here, Bede was simply repeating the earlier use of this zero epact by Dionysius. The Latin word nulla meaning "nothing" was used for this zero epact, whereas other epacts were numbered via Roman numerals or Latin words. Depiction of Bede from the Nuremberg Chronicle, 1493 Bede (Latin Beda), also known as Saint Bede or, more commonly, the Venerable Bede (c. ... The Historia ecclesiastica gentis Anglorum (in English: Ecclesiastical History of the English People) is a work in Latin by the Venerable Bede on the history of the Christian church in England, and of England generally. ... Events Bede completes his Historia ecclesiastica gentis Anglorum February 11 - Pope Gregory III succeeds Gregory II Deaths February 11 - Pope Gregory II See also Unit 731 Categories: 731 ... A calendar era is the year numbering system used by a calendar. ... The Septuagint (LXX) is the name commonly given in the West to the Greek translation of the Hebrew Bible (Old Testament) produced in the third century BC. The Septuagint Bible includes additional books beyond those used in todays Jewish Tanakh. ... Eusebius is the name of several significant historical people: Pope Eusebius - Pope in AD 309 - 310. ... Many cultures have held traditional beliefs that the Earth, or indeed the entire Universe, was brought into being in a grand Creation event by one or more gods. ... This article is about the biblical Adam and Eve. ... Abraham (אַבְרָהָם Father/Leader of many, Standard Hebrew Avraham, Tiberian Hebrew ʾAḇrāhām; Arabic ابراهيم Ibrāhīm) is the patriarch of Judaism, recognized by Christianity, and a very important prophet in Islam. ... Dionysius Exiguus (Dennis the Little, meaning humble) (c. ... Events Bernicia settled by the Angles Ethiopia conquers Yemen The Daisan river, a tributary of the Euphrates, floods Edessa and within a couple of hours fills the entire city except for the highest parts. ... The epact (from Greek: epaktai hèmerai = added days) is, as the second Canon of the Gregorian Calendar reform puts it, nothing else than the number of days which the common solar year of 365 days surpasses the common lunar year of 354 days (Latin: Epacta nihil aliud est quam... Computus (Latin for computation) is the calculation of the date of Easter in the Christian calendar. ... Easter is the most important holiday of the Christian year, observed in March, April, or May each year to celebrate the resurrection of Jesus from the dead after his death by crucifixion (see Good Friday), which Christians believe happened at about this time of year around AD 30-33. ... Events Births Deaths Wihtred, king of Kent Categories: 725 ... Latin is the language originally spoken in the region around Rome called Latium. ... The system of Roman numerals is a numeral system originating in ancient Rome, and was adapted from Etruscan numerals. ...

In chapter II of book I of Ecclesiastical history, Bede stated that Julius Caesar invaded Britain "in the year 693 after the building of Rome, but the sixtieth year before the incarnation of our Lord", while stating in chapter III, "in the year of Rome 798, Claudius" also invaded Britain and "within a very few days … concluded the war in … the fortysixth [year] from the incarnation of our Lord". Although both dates are wrong, they are sufficient to conclude that Bede did not include a year zero between BC and AD: 798 − 693 + 1 (because the years are inclusive) = 106, but 60 + 46 = 106, which leaves no room for a year zero. Note well that the English term "before Christ" (BC) is not a direct translation of the Latin term "before/from the incarnation of our Lord" (itself never abbreviated), but is only a rough equivalent: Incarnation means the conception of Christ, which has been on 25 March since the fourth century, nine months before his birth on 25 December. Bede's singular use of 'BC' continued to be used sporadically throughout the Middle Ages (albeit with a correct year). The first extensive use of 'BC' (hundreds of times) occurred in Fasciculus Temporum by Werner Rolevinck in 1474, alongside years of the world (anno mundi). Gaius Julius Caesar (Latin: IMP·C·IVLIVS·CAESAR·DIVVS¹) (b. ... City motto: Senatus Populusque Romanus – SPQR (The Senate and the People of Rome) Founded 21 April 753 BC mythical, 1st millennium BC Region Latium Mayor Walter Veltroni (Democratici di Sinistra) Area  - City Proper  1290 km² Population  - City (2004)  - Metropolitan  - Density (city proper) 2,546,807 almost 4,000,000 1... A statue of Emperor ClaudiusTiberius Claudius Nero Caesar Drusus (August 1, 10 BC - October 13, 54), originally known as Tiberius Claudius Drusus Nero Germanicus, was the fourth Roman Emperor of the Julio-Claudian dynasty, ruling from January 24th 41 to his death in 54. ... Christ, from the Greek in english known as Χριστός, or Khristós, means anointed, and is equivalent to the Hebrew term Messiah. ... March 25 is the 84th day of the year in the Gregorian calendar (85th in leap years). ... (3rd century - 4th century - 5th century - other centuries) As a means of recording the passage of time, the 4th century was that century which lasted from 301 to 400. ... December 25 is the 359th day of the year (360th in leap years) in the Gregorian Calendar, with 6 days remaining. ... The Middle Ages formed the middle period in a traditional schematic division of European history into three ages: the classical civilization of Antiquity, the Middle Ages, and modern times, beginning with the Renaissance. ... Werner Rolevinck (1425-1502) was a Carthusian monk and wrote important chronicles on the history of westphalia and the world. ... Events December 12 - Upon the death of Henry IV of Castile a civil war ensues between his designated successor Isabella I of Castile and her sister Juana who was supported by her husband, Alfonso V of Portugal. ...

Astronomers

Astronomers include a year 0 immediately before year 1. The first use of an astronomical year 0 is traditionally attributed to Jacques Cassini in his Tables astronomiques (Astronomical Tables, 1740) wherein he explained his reasons for doing so. But Phillipe de La Hire had used it earlier in 1702 in his Tabulæ Astronomicæ (Astronomical Tables) in the form Christum o. ("Christ 0"), without explanation. Both Cassini and La Hire used BC years before their year 0 and AD years thereafter (hence the sequence 1 BC, 0, AD 1). Beginning in the nineteenth century, some astronomers began to use negative years before their year 0, while other astronomers continued to use BC years before their year 0. By the mid twentieth century, all astronomers were using negative years before year 0 (hence the sequence -1, 0, 1). Although 'AD' is omitted from later years, leaving a bare number, a positive sign (+) is sometimes explicitly prefixed to the number. Because of possible confusion with the earlier use of an astronomical BC, only in the modern version can it be said that astronomical year 0 equals the historical year 1 BC. Jacques Cassini (February 8, 1677 - April 18, 1756) was a French astronomer, son of Giovanni Domenico Cassini Cassini was born at the Paris Observatory. ... Events May 31 - Friedrich II comes to power in Prussia upon the death of his father, Friedrich Wilhelm I. October 20 - Maria Theresia of Austria inherits the Habsburg hereditary dominions (Austria, Bohemia, Hungary and present-day Belgium). ... Philippe de la Hire (or Lahire or Phillipe de La Hire), French mathematician and astronomer, was born in Paris on March 18, 1640, and died there on April 21, 1719. ... Events March 8 - William III died; Princess Anne Stuart becomes Queen Anne of England, Scotland and Ireland. ... Alternative meaning: Nineteenth Century (periodical) (18th century — 19th century — 20th century — more centuries) As a means of recording the passage of time, the 19th century was that century which lasted from 1801-1900 in the sense of the Gregorian calendar. ... (19th century - 20th century - 21st century - more centuries) Decades: 1900s 1910s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s The 20th century lasted from 1901 to 2000 in the Gregorian calendar (often from (1900 to 1999 in common usage). ...

ISO 8601:2004 and ISO 8601:2000, but not ISO 8601:1988, explicitly use astronomical year numbering in their date reference systems. The "basic" format for year zero is the four digit form 0000, which equals the historical year 1 BC. Several "expanded" formats are possible: -0000 and +0000, as well as five and six digit versions. Earlier years are also negative four, five or six digit years, which have an absolute value one less than the equivalent BC year, hence -0001 = 2 BC. Because only ISO 646 (7-bit ASCII) characters are allowed, the minus signs are hyphens. ISO 8601 is an international standard for date and time representations. ... The graph of the absolute value function In mathematics, the absolute value (or modulus) of a real number is its numerical value without regard to its sign. ... ISO 646 is an ISO standard that specifies a 7 bit character code from which several national standards are derived, the best known of which is ASCII. Since the portion of ISO 646 shared by all countries specified only the letters used in the English alphabet, other countries using the... There are 95 printable ASCII characters, numbered 32 to 126. ...

In Wikipedia date preferences, the only zero year which is properly converted and linked to 1 BC (and vice-versa) is the ISO year -0000. A bug (or 'feature') causes the ISO basic year of 0000 to be converted and linked to 0. In the opposite direction, 0 is converted to the ISO year 0000 but linked to 0, whereas 0000 is converted to the ISO year 0000 and linked to 0000, redirected to 1 BC. Years can only be converted if an "extended" ISO format of [[YYYY-MM-DD]] or an expanded, extended format of [[-YYYY-MM-DD]] is used. No other ISO date format is an allowable date preference in Wikipedia. Although the isolated year [[0000]] is redirected to 1 BC, [[0]] is not — neither isolated year is converted.

South Asian calendars

All eras used with Hindu and Buddhist calendars, such as the Saka era or the Kali Yuga, begin with a year zero because all of these calendars use elapsed, expired, or complete years, in contrast with most other calendars which use current years. A complete year had not yet elapsed for any date in the year beginning at the epoch, thus that could not be year one — instead, it was year zero. This is similar to the Western method of stating a person's age — people do not reach age one until one year has elapsed since birth (but their age during the year beginning at birth is specified in months, not as age zero). The Hindu calendar used in Vedic times has undergone many changes in the process of regionalization, and today there are several regional Indian calendars. ... The Buddhist calendar is used on mainland southeast Asia in the countries of Cambodia, Laos, Thailand, and Burma in several related forms. ... Centuries: 1st century BC - 1st century - 2nd century Decades: 0s BC - 0s - 10s - 20s - 30s - 40s - 50s - 60s - 70s - 80s - 90s - 100s Years: 73 74 75 76 77 78 79 80 81 82 83 Events Romans conquer the Ordovices, located in present-day northern Wales, as well as the Silures. ... Kali Yuga is also the title of a book by Roland Charles Wagner. ...

Maya historians

Many Maya historians, but not all, assume (or used to assume) that a year zero exists in the modern calendar and thus specify that the epoch of the Long Count of the Maya calendar occurred in 3113 BC rather than 3114 BC. Note that this would require the sequence 1 BC, 0, AD 1 as in early astronomical years. The Maya are people of southern Mexico and northern Central America (Guatemala, Belize, western Honduras, and El Salvador) with some 3,000 years of history. ... The Maya Long Count Calendar is a subset of the Maya calendar used by the Pre-Columbian Maya civilization. ... The Maya calendar is a system of complex and highly developed calendars created by the Maya Civilization of pre-Columbian Mesoamerica. ... (5th millennium BC – 4th millennium BC – 3rd millennium BC - other millennia) Events City of Ur in Mesopotamia (40th century BC). ... (5th millennium BC – 4th millennium BC – 3rd millennium BC - other millennia) Events City of Ur in Mesopotamia (40th century BC). ...

Third millennium

Historians argued that the third millennium began 1 January 2001 because their historical years do not include a year 0, whereas most people assumed that it began 1 January 2000 because that was when the most significant digit of the year changed (1 → 2). Astronomical year numbering cannot be used to support year 2000 as the first year of the third millennium because of uncertainty regarding astronomical millennia. Including year 0 in the first positive millennium (0 to 999) while excluding it from the first negative millennium (-1000 to -1) would be inconsistent. But consistency produces unusual results: either year 0 separates the first positive millennium (1 to 1000) from the first negative millennium (-1000 to -1) or it is included in both (-999 to 0 to 999). (2nd millennium – 3rd millennium – 4th millennium – other millennia) The third millennium is the third period of one thousand years in the Common Era. ... January 1 is the first day of the calendar year in both the Julian and Gregorian calendars. ... 2001 is a common year starting on Monday of the Gregorian calendar. ... January 1 is the first day of the calendar year in both the Julian and Gregorian calendars. ... 2000 is a leap year starting on Saturday of the Gregorian calendar. ... Astronomical year numbering is another method of designating BC/AD years. ...

Media

In the movie Back to the Future, Dr. Emmett Brown, the inventor of a time machine, enters the date of the "birth of Christ" on a keypad as December 25, 0000. Not only does he use the astronomical year number, but he assumes that Jesus was actually born in that year (he was born between 8 BC and AD 9, according to different sources), and also that Christianity's celebration of Christmas on December 25 is a true historical anniversary rather than a traditional date. (Of course, it's possible that he was just being funny and/or showing off.) Back to the Future is a 1985 film by Robert Zemeckis, written by Robert Zemeckis and Robert Gale, and starring Michael J. Fox. ... Doc Emmett L. Brown is a fictional character central to the Back to the Future movies created by Robert Zemeckis and Bob Gale. ... Christ, from the Greek in english known as Χριστός, or Khristós, means anointed, and is equivalent to the Hebrew term Messiah. ... December 25 is the 359th day of the year (360th in leap years) in the Gregorian Calendar, with 6 days remaining. ... Jesus, also known as Jesus Christ*, Jesus of Nazareth, and Jesus the Nazarene, is the central figure in Christianity. ... Christmas (literally, the Mass of Christ) is a holiday in the Christian calendar, usually observed on December 25, which celebrates the birth of Jesus. ... December 25 is the 359th day of the year (360th in leap years) in the Gregorian Calendar, with 6 days remaining. ...

The famous and ficticious theologian Franz Bibfeldt's most famous work relates to the year 0: a 1927 dissertation submission to the University of Worms entitled "The Problem of the Year 0." Franz Bibfeldt is a famous, ficticious theologian and in-joke among American academic theologians. ...

External link

• The Problem of the Year 0 by Franz Bibfeldt (http://magazine.uchicago.edu/9502/Feb95Bibfeldt.html)