The influence of the mestiços began with the slave trade, in which they often served as middlemen between the Portuguese traders and indigenous African kingdoms, leading and accompanying trade caravans into the interior.  Though the slave trade was initially associated with the areas in and around the Kongo kingdom and its capital of São Salvador, Afro-Portuguese traders began to penetrate the central highlands to the south to find new sources of slaves.  Luanda and later Benguela were established as ports to facilitate direct the new trade with Brazil and the other colonies.  The decline of the Kongo due to a series of wars with the Portuguese in the seventeenth century, together with the stronger and more direct connections with colonial traders enjoyed by the Afro-Portuguese led to the eclipse of São Salvador by Luanda as the center of the Angolan slave trade, and by extension, economic activity in the region.