Varronian chronology

The Varronian chronology is the commonly-accepted chronology of early Roman history named after the Roman antiquarian Marcus Terentius Varro. It is from this chronology that the commonly-used dates for the foundation of the city (753 BC), the overthrow of the monarchy (509 BC), the Decimvirates (451–450 BC), the Gallic sack of Rome (390 BC), and the first plebeian consul (366 BC) are derived.^[1] The chronology consists of an ordered list of magisterial colleges (eg pairs of consuls) which, in modern times, are regularly assigned to years BC.

The years given by the Varronian chronology prior to 300 BC should not be accepted as absolute dates.^[2] Years in the chronology are also demonstrably incorrect and it flows four years prior to actual events by 340 BC.^[3] Moreover, Roman historians and antiquarians (most especially Livy and Dionysius of Halicarnassus) also did not all use Varro's scheme. Because both the ordering and absolute position of Varronian years is not well established for this early period, the numeric years derived from it should be taken as "no more than numerical symbols for specific consular years".^[4]

Because the Varronian chronology places the foundation of Rome on 21 April 753 BC, it is also the basis for the Varronian years ab urbe condita (AUC; lit. 'from the founding of the city').^[5] Other chronologies place Rome's foundation in different years BC, meaning that they would place the same event in different years AUC. Romans of the historical period did not use the Varronian chronology or ab urbe condita for everyday timekeeping. Dates were instead kept in reference to a certain year's consuls: eg that an event occurred during the consulship of Marcus Tullius Cicero and Gaius Antonius Hybrida (63 BC).^[6]