The answer is: The Law of Land Warfare, Uniform Code of Military Justice, and Code of Conduct.
The answer may vary from country to country but on an international level the United Nations Charter also provides code of conducts on how modern armies should function in times of war.
These are important in order to provide a moral structure to an Army which can become, as evidenced in history, quite ruthless.
Answer:
Bayeux Tapestry
Explanation:
Bayeux Tapestry, medieval embroidery depicting the Norman Conquest of England in 1066, remarkable as a work of art and important as a source for 11th-century history. English axman in combat with Norman cavalry during the Battle of Hastings, detail from the 11th-century Bayeux Tapestry, Bayeux, France.
Making them slaves to work on their plantations which eventually killed a lot of them.
