In the Historia Augusta, Postumus the Younger figures as one of the so-called Thirty Tyrants who usurped power against the Roman Emperor Gallienus. According to the pseudo-historical list of 'Thirty Tyrants', the Emperor of the Gallic Empire Postumus had a son, also called Postumus, whom he nominated to be first caesar, and later even augustus and co-ruler. Postumus the Younger would have been killed together with his father in 268, during the rebellion of Laelianus (called Lollianus in the Historia).[1]
The historian J. F. Drinkwater dismisses the Historia Augustas reference to Postumus the Younger as a "fiction".[2] There are no references to any son of Postumus on coins or inscriptions from the period.
The author(s) of the Historia asserts that Postumus the Younger was a skilled rhetor, and that his Controversiae were included among Quintilian's Declamationes.[1]