Anno Domini means "[in the] year of [Our] Lord" in Latin. The name comes from Jesus Christ being referred to as "Lord" in Christianity.
The Anno Domini nomenclature for the chronological era in which we live is somewhat controversial for some people. The alternative Common Era (abbreviated C.E.) is often suggested but not universally used.
Anno Domini dating was not the initial choice of Christians in the Mediterranean world. Like all people in the Roman Empire, early Christians dated by their local system. On the pan-Mediterranean scale, that meant the regnal year of the emperor ("in the Xth year of Emperor Such-and-such") and the tax indiction cycle (15 indictions make up a tax cycle, an indicition is near a year in duration, more or less). A great many local systems were also important, such as the year since the foundation of your particular city, the regnal year of the neighboring Persian emperor, and eventually even the year of the reigning Caliph. For example, the City of Rome dated from its foundation in 753 B.C., and the date ab urbe condita, "from the foundation of the city" (abbreviated A.U.C.), shows up on occasion in records. The dating of documents in antiquity and the Middle Ages was a process with a high level of redundancy. This redundancy, in fact, allows historians to construct parallel regnal lists for many kingdoms and polities by comparing chronicles from different regions which include the same rulers.
As the Roman Empire declined, imperial regnal year dating became sloppy, but remained the norm for 400 years in Christian Church circles. The Papacy was in regular contact throughout the Middle Ages with enovys of the Byzantine world, and had a clear enough idea (sudden deaths and deposals intervening) of who was the Byzantine emperor at any one time.
The Anno Domini system was developed by a monk named Dionysius Exiguus (often described as a Scythian) in Rome around the middle of the 6th century, but was not widely adopted. Byzantine chroniclers like Theophanes continued to date each year in their world chronicles on a different and much more popular Judaeo-Christian basis — from the notional Creation of the World as calculated by Christian and Jewish scholars in the first 5 centuries of the Christian era. These eras, sometimes called Anno Mundi, "year of the world" (abbreviated A.M.), by modern scholars, had their own disagreements. The most popular formulation was that established by Eusebius of Caesarea, a historian at the time of Constantine I. The Latin translator Jerome had made a comparison of Eusebius with certain dates deduced from the Old Testament which helped popularize Eusebius's A.M. count in the West.
Almost all Biblical scholars believe that Dionysius was incorrect in his calculation, and that Christ was actually born between 30 B.C. and 4 B.C. The latest bound for the birth of Christ is the death of Herod the Great whose death has been established to occur at 4 B.C. This is not a very controversial point, as no Christian denomination's theology requires the date to be 1 B.C.
The first historian or chronicler to use A.D. as his primary dating mechanism was the Anglo-Saxon monk Bede, in his Ecclesiastical History of the English People, published around 730. Bede was different from historians working in more important places in two ways: First, he was in Northumbria, outside the bounds of the later Roman Empire. Unlike the Mediterranean-focused countries of Italy, France, and Spain, his people had little knowledge of or interest in who the Roman Emperor was in any particular year. Second, he was confronted with the problem of seven Anglo-Saxon kingdoms and their overlapping regnal years. He had also previously written a chronicle going back to Creation, so he had the numbers at his fingertips. He adopted A.D. dating as a way of keeping track of the Anglo-Saxon kingdoms and trying to bring their dates into line with the fragmentary evidence he had for imperial regnal years.
It should be noted that technically for correctness, the "A.D." should appear before the year, e.g. A.D. 2001. This is in keeping with the original Latin meaning: "in the year of our Lord Jesus Christ 2001". However in practice common usage places it ungrammatically at the end, which if taken literally would read "2001 in the year of our Lord Jesus Christ". Other era markings, B.C., C.E., and B.C.E. are placed after the year, e.g., 2001 C.E. They are also generally typeset in small caps.
On the continent of Europe, A.D. was first used as the dominant dating system by Charlemagne and his successors. It was this influence of the Royal Frankish court that popularized the usage and spread it east into German speaking territories. The Carolingian use of A.D. may well have had twin ideological reasons of breaking away from using the Byzantine era and defusing certain strains of apocalyptic thought.
The term "Common Era" has been in use since the late 19th century. Indeed, in its article on "Chronology", the 1908 Catholic Encyclopedia uses the sentence: "Foremost among these [dating eras] is that which is now adopted by all civilized peoples and known as the Christian, Vulgar, or Common Era, in the twentieth century of which we are now living."
This terminology is seen by some Christians, and others, as a move by nonbelievers to make Christianity less visible. By contrast, many groups find the
A.D. teminology to be objectionable for different reasons. For example, Jehovah's Witnesses find the term B.C./A.D. objectionable because it implies that Christ was born on 1 A.D. and their theology requires a different date, which they believe was prophesied in the book of Daniel. In addition, many Jews, Muslims, and some secular academics object to the term A.D. because it implies that Christ is lord.
See also : A.C
The Common Era refers to the conventional numbering of years (in the Julian and Gregorian calendars) from an epoch based on the traditionally reckoned year of the birth of Jesus Christ.
This convention for year numbering was introduced by the christian monk Dionysius Exiguus in 525, although it was not widely used until later.
Years before the epoch were denoted A.C.N. (for Ante Christi Natus, Latin for "before the birth of Christ"), although B.C. ("Before Christ") is now usually used in English.
These abbreviations are placed after the year number, which is counted backward from 1; that is, the first year before the epoch is "1 B.C", the second year before the epoch is "2 B.C", etc. Years after the epoch are denoted A.D. (for Anno Domini, Latin for "in the year of the Lord"). In strict literal latin, the number should follow AD, but in practice, the number has generally come to be placed in front of the letters, e.g. "1 A.D" (there being no year 0), etc.
C.E., an abbreviation for "Common Era" or "Christian Era", is equivalent to A.D. and is preferred by in some writing.
B.C.E., an abbreviation for "Before Common Era" or "Before Christian Era", is equivalent to B.C., and is likewise placed after the year number.
See also: Anno Domini, Astronomical year numberingHistory of Dating in the Christian World
After the Roman Empire
Accuracy of Dating
The Popularization of Anno Domini
Attempts at Alternative Eras in the West
The French Revolution and the Italian Fascists each tried seriously to displace the A.D. system by dating from their own initiation–a non-royal regnal year system. (see French Revolutionary Calendar) The Italian fascists actually used the standard system along with Roman numerals denoting the number of years since the establishment of the fascist government in 1922. Therefore, 1934, for example, was Year XII. It did not replace the standard calendar in the same way the French Revolutionary Calendar did.Alternative Nomenclature for the Same Era
As a substitute for "Anno Domini", many people now use the abbreviation C.E. which is sometimes understood as meaning Common Era and sometimes as Christian Era. Correspondingly, as a substitute for "Before Christ", the abbreviation B.C.E. is used, which is understood either as Before the Common Era or Before the Christian Era. This terminology is preferred by some academics for various reasons, but probably mainly because it need not be interpreted as making religious reference.External link
Moved from Common Era. Much material to be merged...
Due to the dominant influence of Christianity in the development of Western civilization over the last 2,000 years, the initials B.C. (or A.C.N) and A.D. have been used, to a large extent for many centuries. However some groups find it objectionable.