My friend Paul Robinson has a book out in the UK in May from Routledge entitled Military Honour and the Conduct of War: From Ancient Greece to Iraq which should prove to be the definitive answer to your question, Derb. I’ve had the chance to look over his chapters on Greece and Rome, and they cover the subject of the niceties of war in those days comprehensively. Many of the ancient rules that could fairly be described as chivalrous have to do with the religious implications of war, as one would expect. But the concept of “fair play” was far from absent. Alexander the Great refused to surprise the Persians at night, while the Spartans at Sphacteria were a bit miffed when Demosthenes started lobbing arrows at them, but I should defer to anything VDH has to say here.