To the Afrikaners, British rule must have seemed arbitrary at best. One day, the British would try to make nice, helping them yank out another 100 miles of countryside from the locals for their farmlands. After the next electoral cycle, the Afrikaners were suddenly rebuked and told to return the stolen land. All of this wasn’t helped by the tin ear fashion the local bureaucracy operated, or the attempts the British made to impose English on the Dutch speaking populace. When the British government decided that they wanted to ban slavery in 1834, this was the last straw for many farm owning Afrikaners. Deciding they were better off on their own again, they packed their bags and wandered off to the northeast.
In the 1830s and 1840s, these Voortekkers (literally “early movers”) began to carve out their own new kingdoms. This was far from an easy process. Conflict with the Ndebele people and then against the more militant Zulus was a fact of life. At one point in 1838 one of the chief trekkers Piet Rietief and his entire entourage were massacred by the Zulus. Rietief himself was killed last, so he could witness the consequences of his leadership before he died.
Still, the Afrikaners were a hardy bunch and in spite of a lack of formal military training the Voortrekkers had a nasty accuracy with their rifles and a sneaky knack for ambush and defensive tactics. At the appropriately hardcore Battle of Blood River, under five hundred trekkers fended off a Zulu force of more than ten thousand from behind a screen of circled wagons. While it wasn’t the end of the battles with the Zulu, the trekkers had the breathing room they needed to begin founding their own republics far from grabby British hands.
Speaking of which, where were the British in all of this? Still stuck deciding what they wanted to do for the most part. Governors came and went, sometimes allowing the Voortrekkers to go on their merry way, sometimes wandering off on their own campaigns of military expansion. Though the British had shipped off a pile of their own people to Cape Town in 1820, the place was still predominantly Afrikaner. For the moment, the British fired off the equivalent of an Allstaff email insisting they were still in charge, then they let the matter slide. They were embroiled in a never-ending series of wars with the Xhosa people among others, and to a certain degree they must have felt that if the Afrikaners felt like leaving it was good riddance to bad rubbish.
As a sad footnote to the story, the Xhosa had been struggling with the Afrikaners, the British, the Zulus, and the newly established Boers (our trekking Afrikaners) for years by this point. The resulting Xhosa Wars are also sometimes called Africa’s Hundred Year’s War. They sprawl from 1779 to 1879, a time period that more or less covers nine full blown conflicts. In spite of utilizing firearms and some initial successes in some of the wars, the Xhosa could never pull off enough of a win to really push the Europeans off their backs for a while. What really broke the Xhosa though was the emergence of what many historians would term a millennial religious wave. In 1856 a nasty disease swept through a portion of the Xhosa territory, devastating their cattle. One of the villagers, a 16 year old woman named Nongqawuse suddenly had an epiphany. She told her family that three spirits in the bush had told her to burn their crops and slaughter their cattle. While this may have sounded more like the kind of thing shouted at passersby from atop a milk crate in modern downtown Manhattan, she explained that if everyone did so, it was essentially the key to unlocking Armageddon. The dead would rise, everyone would become young again, and most importantly, the white settlers would all die. At first the Xhosa mostly treated this as nonsense, but the vision proved contagious. Unsurprisingly though, the dead declined to wake up and the only thing the slaughter caused was widespread famine. The Xhosa had to turn to the Cape settlers for help, and their power was permanently diminished. It took another generation for the Xhosa to rise again, something prompted by more British stupidity than anything. Today the Xhosa are still a remarkable people, and the world owes them dearly for Nelson Mandela and Archbishop Desmond Tutu, among many others.
 The Zulus especially deserve more of a note here. Their fledgling empire added to the chaos of South African relations at the time, as their own rise to power caused a knock on effect, sending tribes smacking into colonial land, and trekking settlers causing the same effect in reverse.