As the style and level of warfare changed, so did the essential character of the Roman army. Belisarius was held to be a fairly strict commander, and yet the troops under his command were repeatedly guilty of indiscipline, pressuring him into fighting against his better judgment at Callinicum and Rome, and running wild after their success in Africa. Mutiny was nothing new in the Roman army, having been comparatively common even under the Republic, but the truculence and almost routine disobedience of soldiers in the Sixth Century had rarely, if ever, been matched in the past, even during the confusion of civil wars. The literary ideal of the great commander who imposed strict discipline on slack soldiers no longer features in late antiquity, for much of the army’s formal system of regulations and punishment had vanished. Military theory still stressed the importance of keeping soldiers well drilled, but in practice only a small proportion of units—often including the bucellarii of a capable leader—came anywhere near the ideal. As armies grew larger by the standards of the day, the probability increased that a significant number of soldiers would prove extremely unreliable. Centuries of making and breaking emperors had left Roman soldiers unwilling to accept tight discipline, and attempts to restrict their behavior prompted complaints, outright mutiny, or desertion.

From Adrian Goldsworthy’s In the Name of Rome: The Men Who Won the Roman Empire, London: Phoenix, 2003, pp. 423-424.