Next he was commissioned a military tribune in Legio IV Scythica, during which time he distinguished himself, earning dona militaria from the emperor Trajan.
[5] Next he was commissioned legatus legionis or commander of Legio I Adiutrix, then stationed at Brigetio; Alföldy dates this appointment from around 134 to 137.
It is related of him, too, as an instance of his regard for his family, that when Marcus [Aurelius] was mourning the death of his tutor and was restrained by the palace servants from this display of affection, the Emperor [Antoninus Pius] said: "Let him be only a man for once; for neither philosophy nor empire takes away natural feeling".
Marcus claims to have learned from Maximus among other virtues self-control, honesty, gravity of character, and kindness.
From Maximus I learned self-government, and not to be led aside by anything; and cheerfulness in all circumstances, as well as in illness; and a just admixture in the moral character of sweetness and dignity, and to do what was set before me without complaining.
I observed that everybody believed that he thought as he spoke, and that in all that he did he never had any bad intention; and he never showed amazement and surprise, and was never in a hurry, and never put off doing a thing, nor was perplexed nor dejected, nor did he ever laugh to disguise his vexation, nor, on the other hand, was he ever passionate or suspicious.
In the Apologia, Apuleius, author of The Golden Ass, the only completely-surviving Roman novel, attempts to defend himself against a charge of magic, largely by appealing to his judge whom he identifies as Claudius Maximus.
According to Apuleius, Maximus was a pious man who shunned ostentatious displays of wealth and was intimately familiar with the works of Plato and Aristotle.
The Historia Augusta mentions Claudius Maximus in a single sentence in the section on Marcus Aurelius.
Although the Historia Augusta is known for its inaccuracies, Pierre Hadot feels that there is no reason to doubt this portion of the text because it accurately characterizes other philosophers mentioned in the same paragraph.