War being a very ancient activity of man, it is not surprising that over the course of centuries a considerable amount of law has evolved around the subject.
Draper, Gerald I.A.D.
"Rules Governing the Conduct of Hostilities—The Laws of War and Their Enforcement,"
Naval War College Review: Vol. 18
, Article 5.
Available at: https://digital-commons.usnwc.edu/nwc-review/vol18/iss7/5