Upon ascending to power, the great Zulu leader Shaka implemented a number of important civil and military reforms to his growing civilization. In addition to his important innovations to Zulu warfare - he is often credited with the invention of the famous Zulu "buffalo horns" formation, as well as the introduction of the "iklwa," a short stabbing spear that proved enormously successful in combat - Shaka also reorganized Zulu society to better support his military ambitions.
At the age of six, young boys joined Shaka's military as apprentice warriors. (This is a surprising parallel to the way that Spartan boys were raised - though it's unlikely that Shaka ever heard of the Spartans.) The young warriors were trained in "ikhanda" (special military camps). During their training the Zulu boys were imbued with military fervor, put through rigorous physical exercise, and of course instructed in the use of the Zulu's powerful weapons. In battle they carried supplies and extra weapons for the warriors, and it is believed that they occasionally went out on hit-and-run raids against less dangerous enemy tribes. When the boys reached the appropriate age, they became full-fledged warriors. As a result, the Zulu warriors were among the bravest and best-trained soldiers in the world.