section_path: Ancient dating systems/Ancient Rome/Dating from the founding of Rome
section_name: Dating from the founding of Rome
paragraph_text: Dating from the founding of Rome
  
  Another method of dating was ab urbe condita (Latin for "from the founding of the city" of Rome) or anno urbis conditae (Latin for "in the year of the founding of the city"), both abbreviated AUC.
  
  Several epochs for this date were in use by Roman historians, all based on the incomplete surviving list of Roman consuls and the myths of the city's founding by Romulus and Remus. The chronology established by Marcus Terentius Varro in the 1st century BC intercalated several years of dictatorships, a period of anarchy, and a standardized length of reign for all of Rome's former kings to arrive at a year running from 754 – 753 BC, taken as equivalent to the 3rd year of the 6th Olympiad. Because the Parilia had become associated with the founding of the city by his time, he took the specific date to have been 21 April 753 BC. This became the official chronology of the empire by at least the time of Claudius, who held Secular Games in AD 47 to celebrate the city's 800th anniversary. The 900th and 1000th anniversaries were then celebrated in 148 under Antoninus Pius and in 248 under Philip I.
  
  The AUC era was seldom used in the traditional Roman or early Julian calendars. Naming each year by its two consuls or by the emperor's regnal years predominated, with Hadrian 's aurei and sestertii marking the Romaea in AUC 874 (ann dccclxxiiii nat vrb) a notable exception. AUC dating became more common in late antiquity, appearing in Censorinus, Orosius, and others. During the early Middle Ages, some church officials like Boniface IV employed AUC and AD dating together.
  
  Historical Roman dating employed several different dates for the beginning of the year. Modern application of the AUC era generally ignores this, the known mistakes in Varro's own calculations, and the 752 BC epoch used by the Fasti and later Secular Games, such that AD 2025 is generally considered equivalent to AUC 2778 (2025 + 753).