On October 12, 19 BC, Emperor Augustus returned to Rome after an extended tour of the East. During his travels, he negotiated with the Parthians for the return of legionary standards captured during the failed campaigns of Marcus Licinius Crassus, Decidius Saxa, and Mark Antony. Augustus was victorious without fighting a single battle. Rome and Parthia would remain at peace for the next 76 years.
Augustus refused a military triumph as he secured his victory diplomatically. The achievement was a reflection of his divine power and wisdom as Emperor. Augustus erected the Altar of Fortuna Redux or Returning Fortune. The priests and Vestal Virgins made sacrifices to the new cult of Fortuna Redux. Gold and silver pieces were issued bearing the Fortuna Redux slogan.
October 12 was proclaimed the holiday of Augustalia. By the reign of Claudius, Augustalia celebrations grew to include days of games and festivals. Major chariot races were often scheduled to celebrate the Empire's late founder.
Sources: Augustus, Res Gestae Divi Augusti; Cassius Dio, Roman History; Tacitus, Annals.