Ancient Warfare: Reader\'s questions Special?

[Justin of the New Yorkii]

The ancient origins of international law; arbitration amongst the Greek city-states, the Olympic Truce, observation of religious festivals during wartime. I know, they didn't have international law in the modern sense, but there were cases of states observing international norms even when they ran contrary to their interests.
Also could list the most notorious violators of ancient "international law."