Ab epistulis was the chancellor's office in the Roman Empire with responsibility for the emperor's correspondence.
[7] Narcissus apparently worked as ab epistulis, because he was in charge of the grammata of Claudius against Agrippina.
[7] The famous biographer Suetonius Tranquillus was ab epistulis to Hadrian,[8] according to the Historia Augusta until he was replaced for too-close relations with Empress Sabina.
[4] Marcus was impressed by the orator Hadrian of Tyre, so he offered him the job ab epistulis to recognise his excellence.
[4] Aelius Antipater was the ab epistulis of the emperor Caracalla, who defined him "my friend and teacher, entrusted with the composition of Greek letters".