Saint Maurice was the leader of the Theban Legion. The traditional story is that the legion, entirely composed of Christians, had been called from Thebes in Egypt to go to Gaul, to assist Maximian, which they did valiently. However, when Maximian ordered them to harass some local Christians, they refused, and Maximian ordered the unit punished. Every tenth soldier was killed, a military punishment known as decimation. More orders followed, they still refused, in part to encouragement from St. Maurice, and a second decimation was ordered. In response to their refusal to use violence against fellow Chistians, Maximian ordered all the remaining members of the 6,600 unit executed.
So reads the earliest account of their martyrdom, according to the letter Eucherius, bishop of Lyons (c.434 - 450), wrote to his fellow bishop Salvius. But several details of this story conflict with known historical fact: one is that decimation had not been used to discipline a Roman legion for centuries: the previous documented execution of this sentence was in the reign of Galba, who ordered this done to a formation of marines that Nero had formed into a legion, and who demanded an eagle and standards. Another fact that conflicts with the historical record is the statement that Christians filled out an entire legion, when it is clear that Christians commonly refused to serve in the military until Constantine's time, at the earliest.
David Wood has argued that this was a pious fabrication by bishop Theodore of Octodurum sometime between 388 and 394, whom Eucehrius cites as his source of this story, to encourage his contemporary Christians serving in the Imperial army to ignore the orders their pagan superiors and instead side with the Christians. If this is true, it would not be an isolated fabrication for the purposes of propaganda: Ambrose, bishop of Milan, uncovered the remains of at least four people he claimed were saints, yet no records existed of their existence, let alone their martyrdom.
St. Maurice is traditionally depicted in full armor, in Italy with a red cross. In the Magdeburg and other eastern German depictions he is often shown as a Moor.