Because of the Spanish and Nahuatl text accompanying some manuscripts, including the Aubin, many of the logographic signs are correlated to Spanish text, allowing scholars to assign dates from the Christian calendric system to dates in the Aztec system. The deciphering of the calendar used by Aztec and Mixtec societies is essential to the understanding of the time in which certain events occurred, as well as to the understanding of the Aztec conception of time.
Aztec civilization used the 52-year structure in which years with numbers 1-13 and four different names (out of the names used to name days) combine so that a year name is repeated once every 52 years. At the close of each cycle would be a New Fire ceremony to extinguish the fire from the old cycle and light a new one.
The deciphering of the Aztec calendar has allowed the lining up of Aztec dates with European calendric dates, showing that these histories cover over 900 years.[i] Matching up these dates brings out an obvious discrepancy in European and Aztec concepts of time. While European modern time continues forward infinitely, starting at a religiously assigned year 1, Aztec time is cyclical, with any given calendar year happening every 52 years. Rather than a progressive march forward, a point in time is inseparable from its past and its future. This awareness of repetition in time shows up in the arc of migration and the ongoing march of time through the imperial period.
[i] Smith, Picture Writing from Ancient Southern Mexico,22.