In far southwestern Angola, three categories of Bantu-speaking peoples have been distinguished. Two of them, the Ovambo and the Herero, were more heavily represented elsewhere: the Ovambo in Namibia and the Herero in Namibia and Botswana. The Herero dispersion, especially that section of it in Botswana, was the consequence of the migration of the Herero from German South West Africa (present-day Namibia) after their rebellion against German rule in 1906. The third group was the Nyaneka-Humbe. Unlike the other groups, the Nyaneka-Humbe did not disperse outside Angola. In 1988 the Nyaneka-Humbe (the first group is also spelled Haneca; the latter group is also spelled Nkumbi) constituted 3 percent of the population. The Ovambo, of which the largest subgroup were the Kwanhama (also spelled Kwanyama), made up an estimated 2 percent of the Angolan population. In the second half of the nineteenth century, the Kwanhama Kingdom of southern Angola was a powerful state involved in a lucrative trade relationship with the Portuguese, who, together with the Germans, occupied Kwanhama territory in the early twentieth century. In the 1980s, the Ovambo were seminomadic cattle herders and farmers. The Herero constituted no more than 0.5 percent of the population in 1988. Traditionally, the Herero were nomadic or seminomadic herders living in the arid coastal lowlands and in the mountainous escarpment to the east in Namibe, Benguela, and Huíla provinces. Many Herero migrated south to Namibia when the Portuguese launched a military expedition against them in 1940 following their refusal to pay taxes.