7. Rome: Total War – City massacres in breach of traditional laws of war.
Modern Christian theories of ‘just war’ began after the fall of Rome, but the idea that there can be rules to war stretches back to Cicero in the time of Rome: Total War. As Thomas Aquinas would later formulate it, a just war must not merely be just in its cause, but waged justly, and peace must be a central motive. This is pretty much the opposite of the strategy that R:TW players quickly discover is optimal: massacring the population of every city you capture.
In Rome, cities can be very hard to govern, especially towards the end of the game and far from your empire’s capital. Civilian populations are unruly and intractable, slowing economic output and requiring large, costly garrisons. At this stage, many players learn to immediately kill of 75% of the population upon capture – which makes them far easier to manage. While such sackings were common in the ancient world, they were often justified by the claim that the population in question had been offered, and refused, the chance to surrender. In-game, no such offer is in evidence.