Although warfare has changed dramatically since the Geneva Conventions of 1949, they are still considered the cornerstone of contemporary international humanitarian law. They protect combatants who find themselves hors de combat, and they protect civilians caught up in the zone of war.
Mesopotamia--this early civilization traces connections to trade as early as 2300 BC connecting to Egypt and the Indus Valley.
Through trade, ideas and collective learning occurred spreading to these Bronze Age civilizations. Eventually this spread to more growing civilizations to the north (Greece) and east (Persia).