Archeological evidence of warfare dates back about 10,000 years, to the time of the agricultural revolution — when people departed from the hunting/gathering culture and started forming farming communities. The killing of groups by other groups can be traced to prehistoric times, around 9700 B.C. With the emergence of war, a people joined together to fight a common enemy and became warriors. Throughout history, there have been many daring, brutal, and brave warrior societies. Here are five that stand out.