Shaka was born the son of Senzakhona, the Zulu chief, and the Langeni princess Nandi. Senzakhona had unintentionally impregnated Nandi, but was obligated to take her as his third wife her in spite of the fact that she was from the lowly regarded Langeni clan. Due to this, she and her son were treated as outcasts and were unhappy. When an incident caused Senzakhona to banish Nandi and her children, they had to return to her people. Because an expelled woman was looked upon as being a diminished woman, Nandi and her children were even more unhappy with the Langeni. They were humiliated and Shaka was bullied by the other boys, helping form Shaka?s personality and ambition. He became isolated, showing affection only to his mother.
Shaka lived with the Langeni until about the age of fifteen, when he met his father for the first time since his banishment and they quarreled, causing Nandi to send Shaka to live with her aunt for fear for his safety.
Nandi?s aunt lived with the Mthethwa, a very powerful group. Here he learned many of the skills that later made him a successful warrior.
That was also where he came under the guidance of Dingiswayo, an important factor in the shaping of his thinking.
Dingiswayo introduced age regiments where young men were called up to serve for a part of every year, men from the same households and villages were put in different regiments, their allegiance primarily to the ruler of the chiefdom, Dingiswayo, and secondarily to their local chiefs.
In his early twenties, Shaka was conscripted into the Mthethwa army, as he was a skilled warrior, he ascended the ranks to command his own regiment. This put him in a position to introduce some ideas that he had. The traditional throwing spear, the assegai, was no good for hand-to-hand combat, and left the warrior defenceless after he threw it, so Shaka introduced the short stabbing spear. His warriors used their shields to deflect the initial rain of assegais, then advanced on a nearly defenceless enemy with their stabbing spears.
In a style fitting his reputation for bravery, Shaka demonstrated his stabbing spear in a battle with the Butelezi. Responding to the challenge of a Butelezi warrior, Shaka strolled from his regiment to the Butelezi, less than a hundred metres away. He deflected the first two spears thrown by the warrior, and when he came close to the warrior, Shaka hooked his shield to the warrior?s, and pulled them to his left, between himself and the Butelezi warrior?s spear. He thrust his stabbing spear into the man, killing him, then jumped over the body and approached the rest of the Butelezi regiment and his regiment followed. Dingiswayo was witness to this, and immediately promoted him.
Tactically, Shaka introduced and refined the ?cow?s horns? formation, already in operation in other groups, but not to the same level of organisation. The tactic involved two parts to the regiment, a main ?chest? section, and the horns. The chest engaged the enemy in the normal way while the flanking ?horns? encircled the enemy, leaving them no escape. With these tactics and the use of spies to make a surprise attack possible, Shaka was an extremely successful military leader.
When his father died, Shaka was not the named heir, but becoming the chief of the Zulu was vital to his future plans. The named heir had a timely death, allowing Shaka to take the chieftainship.
One of the first changes he implemented was to conscript all males under the age of forty into regiments where they would learn to use the weapons and tactics that Shaka had developed with the Mthethwa. He also introduced the idea of ?unlimited warfare?, whereby the enemy was not only defeated in battle, but ruling family were eliminated, the women and children were massacred, sending refugees to burden other kingdoms.
In contrast to Dingiswayo?s idea of confederacy, Shaka set out create a single chiefdom from the independent kingdoms he conquered.
At its height, the Zulu drove out those who would not join his unified chiefdom, causing the mfecane.