Answer:
Trade in the East African interior began in African hands. In the southern regions Bisa, Yao, Fipa, and Nyamwezi traders were long active over a wide area. By the early 19th century Kamba traders had begun regularly to move northwestward between the Rift Valley and the sea. Indeed, it was Africans who usually arrived first to trade at the coast, rather than the Zanzibaris, who first moved inland. Zanzibari caravans had, however, begun to thrust inland before the end of the 18th century. Their main route thereafter struck immediately to the west and soon made Tabora their chief upcountry base. From there some traders went due west to Ujiji and across Lake Tanganyika to found, in the latter part of the 19th century, slave-based Arab states upon the Luapula and the upper reaches of the Congo. In these areas some of those who crossed the Nyasa-Tanganyika watershed (which was often approached from farther down the East African coast) were involved as well, while others went northwestward and captured the trade on the south and west sides of Lake Victoria. Here they were mostly kept out of Rwanda, but they were welcomed in both Buganda and Bunyoro and largely forestalled other traders who, after 1841, were thrusting up the Nile from Khartoum. They forestalled, too, the coastal traders moving inland from Mombasa, who seemed unable to establish themselves beyond Kilimanjaro on the south side of Lake Victoria. These Mombasa traders only captured the Kamba trade by first moving out beyond it to the west. By the 1880s, however, they were operating both in the Mount Kenya region and around Winam Bay and were even reaching north toward Lake Rudolf
