Essentially most characters would only need to know things between 50CE through to the current time.
AeRo is mostly AU after Caligula. However, the births of a few important dates were put in place to assist in working out ages, etc.
DRUSUS CLAUDIUS CAESAR AUG. (IV) & AULUS VOLUMNIUS DECIANUS.
MANIUS ACILIUS GLABRIO LEONTIUS & MARCUS HORATIUS ATTICUS.
GAIUS AURELIUS COTTA & SERVIUS TULLIUS CARMINUS.
QUINTUS CAECINA TUSCUS & LUCIUS FLAVIUS FAUSTUS MAJOR
MARCUS RUFIUS HONORIUS CAESAR (II) & GNAEUS JUVENTIUS GETA