It is unclear when Bantu-speaking peoples first moved into the country from the north, although AD 600 seems to be a consensus estimate. In that era, the ancestors of the modern-day Kalanga moved into what is now the north-eastern areas of the country. These proto-Kalanga were closely connected to states in Zimbabwe as well as to the Mapungubwe state. These states, located outside of current Botswana’s borders, appear to have kept massive cattle herds in what is now the Central District—apparently at numbers approaching modern cattle density. This massive cattle-raising complex prospered until 1300 AD or so, and seems to have regressed following the collapse of Mapungubwe. During this era, the first Tswana-speaking groups, the Bakgalagadi, moved into the southern areas of the Kalahari. All these various peoples were connected to trade routes that ran via the Limpopo River to the Indian Ocean, and trade goods from Asia such as beads made their way to Botswana most likely in exchange for ivory, gold, and rhinoceros horn.
The arrival of the ancestors of the Tswana-speakers who came to control the region has yet to be dated precisely. Members of the Bakwena, a chieftaincy under a legendary leader named Kgabo II, made their way into the southern Kalahari by AD 1500, at the latest, and his people drove the Bakgalagadi inhabitants west into the desert. Over the years, several offshoots of the Bakwena moved into adjoining territories. The Bangwaketse occupied areas to the west, while the Bangwato moved northeast into formerly Kalanga areas. Not long afterwards, a Bangwato offshoot known as the Batawana migrated into the Okavango Delta, probably in the 1790s.
Effects of the Mfecane:
The first written records relating to modern-day Botswana appear in 1824. What these records show is that the Bangwaketse had become the predominant power in the region. Under the rule of Makaba II, the Bangwaketse kept vast herds of cattle in well-protected desert areas, and used their military prowess to raid their neighbors. Other chiefdoms in the area, by this time, had capitals of 10,000 or so and were fairly prosperous. This equilibrium came to end during the Mfecane period, 1823–1843, when a succession of invading peoples from South Africa entered the country. Although the Bangwaketse were able to defeat the invading Bakololo in 1826, over time all the major chiefdoms in Botswana were attacked, weakened, and impoverished. The Bakololo and Amandebele raided repeatedly, and took large numbers of cattle, women, and children from the Batswana—most of whom were driven into the desert or sanctuary areas such as hilltops and caves. Only after 1843, when the Amandebele moved into western Zimbabwe, did this threat subside.
During the 1840s and 1850s trade with Cape Colony-based merchants opened up and enabled the Batswana chiefdoms to rebuild. The Bakwena, Bangwaketse, Bangwato and Batawana cooperated to control the lucrative ivory trade, and then used the proceeds to import horses and guns, which in turn enabled them to establish control over what is now Botswana. This process was largely complete by 1880, and thus the Bushmen, the Kalanga, the Bakgalagadi, and other current minorities were subjugated by the Batswana.