Ab urbe condita

Use

Prior to the Roman state's adoption of the Varronian chronology – created by Titus Pomponius Atticus and Marcus Terentius Varro – there were many different dates posited for when the city was founded. This state of confusion required picking a canonical founding date for one to use an AUC date. The Varronian chronology, constructed from fragmentary sources and demonstrably about four years off of absolute events , placed the founding of the city on 21 April 753 BC. This date, likely arrived at by mechanical calculation but accepted with a variance of one year by the Augustan-era fasti Capitolini, has become the traditional date.

From the time of Claudius () onward, this calculation superseded other contemporary calculations. Celebrating the anniversary of the city became part of imperial propaganda. Claudius was the first to hold magnificent celebrations in honor of the anniversary of the city, in AD 47, the eight hundredth year from the founding of the city. Hadrian, in AD 121, and Antoninus Pius, in AD 147 and AD 148, held similar celebrations respectively.

In AD 248, Philip the Arab celebrated Rome's first millennium, together with Ludi saeculares for Rome's alleged tenth saeculum. Coins from his reign commemorate the celebrations. A coin by a contender for the imperial throne, Pacatianus, explicitly states "[y]ear 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 Sæculum Novum.

Calendar era

The Anno Domini (AD) year numbering was developed by a monk named Dionysius Exiguus in Rome in , as a result of his work on calculating the date of Easter. Dionysius did not use the AUC convention, but instead based his calculations on the Diocletian era. This convention had been in use since AD 293, the year of the tetrarchy, as it became impractical to use regnal years of the current emperor. In his Easter table, the year was equated with the 248th regnal year of Diocletian. The table counted the years starting from the presumed birth of Christ, rather than the accession of the emperor Diocletian on 20 November AD 284 or, as stated by Dionysius: "sed magis elegimus ab incarnatione Domini nostri Jesu Christi annorum tempora praenotare" ("but rather we choose to name the times of the years from the incarnation of our Lord Jesus Christ"). Blackburn and Holford-Strevens review interpretations of Dionysius which place the Incarnation in 2 BC, 1 BC, or AD 1.

The year AD 1 corresponds to AUC 754, based on the epoch of Varro. Thus:

References

References

1. "Definition of AB URBE CONDITA".
2. "Definition of ANNO URBIS CONDITAE".
3. (2014). "The Cambridge Companion to the Roman Republic". Cambridge University Press.
4. Forsythe, Gary. (2005). "A critical history of early Rome". University of California Press.
5. Cornell, Tim. (1995). "The beginnings of Rome". Routledge.
6. "Annals XI". Clarendon Press.
7. (20 November 2017). "saeculum". Oxford University Press.
8. (1860). "Records of Roman history, from Cnaeus Pompeius to Tiberius Constantinus, as exhibited on the Roman coins". [[John Bowyer Nichols]].
9. Thomas, J. David. (January 1971). "On Dating by Regnal Years of Diocletian, Maximian and the Caesars". Chronique d'Égypte.
10. [[Jacques Paul Migne
11. Blackburn, B. & Holford-Strevens, L, ''The Oxford Companion to the Year'' (Oxford University Press, 2003 corrected reprinting, originally 1999), pp. 778–780.