International Humanitarian Law
SINCE ANCIENT TIMES, SOME WHO TAKE PART IN ARMED COMBAT have recognized that placing certain limits on the way in which they conduct hostilities can be advantageous. It can be a sign of civilized behavior, enhancing their own prestige; it may be a way to encourage their opponents to behave in a similar manner; and it may contribute to the reestablishment of peaceful relations in which the rule of law prevails. Whether or not these limits confer advantages, they do most often have the effect of asserting a commitment to humane principles.
A story Herodotus tells indicates that the value of such limits was recognized by the Persian king Xerxes. In violation of the customs of war, Sparta (known also as Lacedaemon) had murdered heralds sent by Xerxes to conduct negotiations. Subsequently, Sparta sent envoys to the Persians, who were supposed to pay for those crimes with their own lives. When they arrived, however, Xerxes refused to kill them. He said he “would not be like the Lacedaemonians, for they have broken what is customary usage among all mankind by killing the heralds; but I will not myself do what I rebuke them for, nor by counterkilling will I release the Lacedaemonians’ guilt.”
The notion that truly “civilized” peoples should set boundaries even in war was not confined to those who founded Western civilization. The Chinese military strategist Sun Tzu, whose writings about the relationship between warfare and politics anticipated much contemporary thought on such matters, also discussed the subject in the period not long after Herodotus. He advised armies to “treat captives well, and care for them.”