What outsiders traded with Southern Africans before the Europeans arrived?

Explanation:

The first Europeans to enter Southern Africa were the Portuguese, who from the 15th century edged their way around the African coast in the hope of outflanking Islam, finding a sea route to the riches of India, and discovering additional sources of food. They reached the Kongo kingdom in northwestern Angola in 1482–83; early in 1488 Bartolomeu Dias rounded the southern tip of the continent; and just over a decade later Vasco da Gama sailed along the east coast of Africa before striking out to India. Although the voyages were initially unpromising, they marked the beginning of the integration of the subcontinent into the new world economy and the dominance of Europeans over the indigenous inhabitants.

a historian who compares the expansion of political systems to the expansion of economic systems to the expansion of economic systems is organizing history by theme.

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