Probably born about 160 AD, Marius Maximus’ military career began in the reign of Marcus Aurelius, when he was Tribunus laticlavius of the Legio XXII Primigenia.
It was during this time he fought at the Battle of Lugdunum against Clodius Albinus, after which he was appointed Legatus Augusti pro praetore (or governor) of Gallia Belgica, which he held probably until AD 199.
Although he held no post during the reign of Elagabalus, under Alexander Severus he was made consul for a second time in AD 223, alongside Lucius Roscius Aelianus Paculus Salvius Julianus.
As an eyewitness who experienced at least seven of these reigns from positions of authority, Maximus could have taken up the writing of history like his contemporary Dio Cassius, but he preferred the anecdotal and, indeed, frivolous forms of biography.
His writings come in for adverse criticism from Jerome, Ammianus Marcellinus, and also the anonymous author of the Historia Augusta, who nevertheless cites him directly at least twenty-six times (apparently in most cases quoting or summarizing passages from Marius's lost work) and probably uses him in many places elsewhere.
Marius's intention seems to have been to follow and out-perform Suetonius in serving up gossip, spicy details of the Emperors’ private lives, cynical comments, scandalous anecdotes, and curiosa.
There is however a contrary view, most convincingly put by Sir Ronald Syme, who points out that all the passages in which Marius is cited by name can be shown to be interpolations in the author’s main narrative, brought in to provide colour, frivolous anecdote or critical comment.
Examples include the meat dish (tetrafarmacum) that Aelius Verus invented, Hadrian’s supposed expertise in astrology, various stories to the discredit of Marcus Aurelius and his consort Faustina the Younger, the Senate’s craven catalogue of acclamations for Commodus, and so on.