The mood, pose and facial features of the Roman statue of an Emperor, for instance, was typically solemn and unsmiling. As Rome grew more confident from the reign of Augustus , its leaders might appear in more magnanimous poses, but gravitas and an underlying sense of Roman greatness was never far from the surface. Another important characteristic of Rome's plastic art was its realism. The highly detailed reliefs on Trajan's Column and the Column of Marcus Aurelius, for instance, are perfect illustrations of this focus on accurate representation, and have been important sources of information for scholars on many aspects of the Roman Legion, its equipment and battle tactics.