Ab urbe condita


 * For the book Ab Urbe Condita see .

Ab Urbe condita (related with Anno Urbis conditae: AUC or a.u.c.) is for "from  of the City ", traditionally set in 753 BC. It was used to identify the Roman year by a few Roman historians. Modern historians use it much more frequently than the Romans themselves did; the dominant method of identifying Roman years was to name the two s who held office that year. Before the advent of the modern critical edition of historical Roman works, AUC was indiscriminately added to them by earlier editors, making it appear more widely used than it actually was. The regnal year of the emperor was also used to identify years, especially in the after  required its use in 537. Examples of usage are principally found in German authors, for example Mommsen's History of Rome.

Significance






From Emperor onwards, 's calculation (see below) superseded other contemporary calculations. Celebrating the anniversary of the city became part of imperial. Claudius was the first to hold magnificent celebrations in honor of the city's anniversary, in, eight hundred years after the founding of the city. In 121,, and in 147/8, held similar celebrations.

In 248, celebrated Rome's first, together with  for 's alleged tenth. s from his reign commemorate the celebrations. A coin by a contender for the imperial throne,, explicitly states "Year one thousand and first", which is an indication that the citizens of the Empire had a sense of the beginning of a new era, a Saeculum Novum.

When the Roman Empire turned in the following century, this imagery came to be used in a more  sense.

Calculation by Varro
The traditional date for the founding of Rome of, , was initiated by. Varro may have used the consular list with its mistakes, and called the year of the first consuls "245 ab urbe condita", accepting the 244-year interval from for the kings after the foundation of Rome. The correctness of Varro's calculation has not been proved scientifically but is still used worldwide.

Calculation by Dionysius Exiguus
The system was developed by a monk named  in Rome in 525, as an outcome of his work on calculating the date of Easter. In his Easter table Dionysius equates the year AD 532 with the regnal year 248 of Emperor Diocletian. He invented a new system of numbering years to replace the Diocletian years that had been used in an old Easter table because he did not wish to continue the memory of a tyrant who persecuted Christians. At the beginning, his time calculation was limited on a small circle in Rome. It counted the years no longer after the accession of the emperor and Christian pursuer (20 November 284), but starting from "incarnatione Domini", the birth of Christ. Exiguus is writing: "sed magis elegimus ab incarnatione Domini nostri Jesu Christi annorum tempora praenotare..." Because Dionysius did not place the Incarnation in an explicit year, competent scholars have deduced both AD 1 and 1 BC. Later it was calculated by scholars that the year AD 1 corresponds to the Roman year DCC.LIV ab urbe condita Emperor was called Imperator Caesar Divi filius in the years 30 - 27 BC. This time could be forgotten. And a "" does not exist in the Christian calendar:

...1 ab urbe condita = 753 before Christ ...2 ab urbe condita = 752 BC

...3 ab urbe condita = 751 BC ... 750 ab urbe condita = 4 BC (Death of ; Christ was born before the death of Herod)

751 ab urbe condita = 3 BC

752 ab urbe condita = 2 BC

753 ab urbe condita = 1 BC

754 ab urbe condita = 1

755 ab urbe condita = 2 AD

Alternative calculations
According to the foundation of Rome took place 437 years after the capture of Troy (1182 BC). It took place shortly before an of the Sun that was observed at Rome on,  and had a magnitude of 50.3%. Its beginning occurred at 16:38, its middle at 17:28, and its end at 18:16.

However, according to Lucius Tarrutius of Firmum, were conceived in the womb on the 23rd day of the  Choiac, at the time of a total eclipse of the Sun. (This eclipse occurred on, , with a magnitude of 62.5% at Rome. Its beginning took place at 6:49, its middle at 7:47 and its end at 8:51.) He was born on the 21st day of the month Thoth. The first day of Thoth fell on in that year. Rome was founded on the ninth day of the month Pharmuthi, which was, as universally agreed. The Romans add that about the time Romulus started to build the city, an eclipse of the Sun was observed by Antimachus, the Teian poet, on the 30th day of the lunar month. This eclipse on, (see above) had a magnitude of 54.6% at Teos, Asia Minor. It started at 17:49; it was still eclipsed at sunset, at 19:20. Romulus vanished in the 54th year of his life, on the Nones of Quintilis (July), on a day when the was darkened. The day turned into night, which sudden darkness was believed to be an eclipse of the Sun. It occurred on, , with a magnitude of 93.7%, beginning at 5:04 and ending at 6:57. (All these eclipse data have been calculated by Prof. Aurél Ponori-Thewrewk, retired director of the Planetarium of Budapest.) Plutarch placed it in the 37th year from the foundation of Rome, on the fifth of our July, then called Quintilis, also states that Romulus ruled for 37 years. He was slain by the senate or disappeared in the 38th year of his reign. Most of these have been recorded by, Florus, (Book I, I), Florus Cicero, Dio (Dion) Cassius and Dionysius of Halicarnassus (L. 2). Dio in his Roman History (Book I) confirms this data by telling that Romulus was in his 18th year of age when he had founded Rome. Thus, three eclipse calculations may support the suggestion that Romulus reigned from 746 BC to 709 BC, and Rome was founded in 745 BC.

(c. 250 BC) tells that Roman consuls started for the first time 239 years after Rome's foundation (Enciclopedia Italiana, XIV, 1951: 173). Livy (I, 60) gives almost the same, 240 years for that interval. tells that 28 years after the expulsion of the last Roman king crossed over to, and that event is fixed to 478 BC by two s.