Between roughly 1815 and 1840 a period of intense warfare, state formation and migration reshaped the interior of southern Africa. South African History Online sets out the causes now generally accepted: severe drought from about 1800 to 1820, intensified by the Tambora eruption of 1815 and remembered in oral tradition as the time of eating up everything; competition among chiefdoms for the ivory and slave trade through Delagoa Bay; the military and political consolidation associated with Shaka's Zulu kingdom; and the destabilising pressure of the Cape Colony frontier, the arms trade and slave raiding from the south and east. The consequences were the formation of the Zulu, Sotho, Swazi, Ndebele and Gaza states, the movement of Ngoni and Kololo groups as far as Tanzania, Malawi and Zambia, and depopulation of parts of the highveld into which Boer trekkers moved from 1836. Julian Cobbing's intervention in 1988 argued that the whole concept had been constructed by colonial and apartheid historiography to present black-on-black destruction and to justify white land claims.
Warfare and state formation among Nguni and Sotho-Tswana chiefdoms, in a period of drought and expanding slave and ivory trading, displaced populations across the southern African interior
No defensible denominator exists, and the event's historiography is itself contested. Julian Cobbing's 1988 critique reframed the Mfecane as driven substantially by Portuguese slave raiding from Delagoa Bay and Cape labour demand rather than by Zulu state formation alone, and in the ensuing debate both the death tolls - traditionally given as one to two million - and the underlying population of the interior were shown to rest on colonial-era assertion. Estimates of the Bantu-speaking population between the Limpopo and the Cape frontier around 1815 range from about 1.5 to 4 million.
The figure of one to two million deaths repeated in older accounts has no demographic basis: there was no census, no tax register and no administration in the affected region, and South African History Online records that contemporary historians consider these estimates exaggerated and much of the disruption to have been flight rather than mortality. No replacement figure has been established, and giving one would be false precision. Deaths certainly occurred from warfare, famine and the collapse of food production, and are attested in oral tradition and in the accounts of missionaries and traders.
South African History Online records documented warfare, famine and the destruction of communities across the affected region, drawing on oral traditions collected in the nineteenth century, missionary and trader accounts, and the archaeology of abandoned settlements; the scale and the attribution of that violence are the substance of the Cobbing debate.
South Africa, Zimbabwe, Malawi, Zambia