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.
QUINTUS FLAVIUS CAESAR ALEXANDER & TIBERIUS FABIUS MAXIMUS
MARCUS AEMILIUS SCAURUS AND QUINTUS FLAVIUS ALEXANDER (II).
DR. CLAUDIUS CAE. AUG. (I) & S. JULIUS FIDELIS
Marcus Aemilius Scaurus Alexander and Marcus Valerius Maximus