 Most modern historians tacitly assume that it began on the day the consuls took office, and ancient documents such as the "Fasti Capitolini" which use other AUC systems do so in the same way.However, Censorinus, writing in the 3rd century AD, states that, in his time, the AUC year began with the Parilia, celebrated on 21 April, which was regarded as the actual anniversary of the foundation of Rome.Many local eras, such as the Era of Actium and the Spanish Era, were adopted for the Julian calendar or its local equivalent in the provinces and cities of the Roman Empire.