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AERA. - Era, or Epoch, is the point of commencement, from which years are reckoned, as taken from the date of some memmorable event. Thus in Christendom, especially Christian Europe, we compute the number of years, from the era of Our Lord 's incarnation. The different cities and peoples af antiquity by whom the Greek language was used, began the year from the season of autumn, namely, about the autumnal equinox, or from the calends of September - although, after the correction of the calendar, promulgated under Julius Caesar, the beginning of the year was taken from the calends of January, in some Greek cities influenced by Rome. - The commencement of numbering is expressed both in the Varronian years from the foundation of Rome, and in the vulgar era from the birth of Christ. The year U. C. (Urbis Conditae), according to Terentius Varro, began 753 years before the Christian era. -  According to Cato, Rome was founded in B. C. 751; according to Polybius in B. C. 750; according to Fabius Pictor in 747. - Visconti (Iconographie Romaine, i. p. 14, 8vo. edit.) says - "Je préfère, avec la plupart des chronologistes, le calcul de Varron, qui fut le plus suivi par les anciens, depuis le siècle d 'Auguste."
From amongs the more illustrious epochs of cities, and those of more frequent occurence, the following are selected as bearing relation to Roman History: -

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