Colonial legislation discriminated against Africans on cultural grounds. Colonial legislation submitted Africans to forced labour, to pass laws and to segregation in schools. That most Africans were perceived to engage in "uncivilized behaviour" by the Portuguese created a low opinion of Africans as a group among Europeans. The uneducated Portuguese immigrant peasants in urban areas were frequently in direct competition with Africans for jobs and demonstrated jealousies and racial prejudice. Between the urban and rural sectors of the society lied a steadily increasing group of Africans who were loosening their ties with rural villages and starting to participate in the urban economy, to settle in suburbs, and to adopt European customs. Members of this group would later become active participants in the independence movement. When Portuguese explorers reached East Africa in 1498, Swahili commercial settlements had existed along the Swahili Coast and outlying islands for several centuries. From about 1500, Portuguese trading posts and forts became regular ports of call on the new route to the east. The voyage of Vasco da Gama around the Cape of Good Hope into the Indian Ocean in 1498 marked the Portuguese entry into trade, politics, and society in the Indian Ocean world. The Portuguese gained control of the Island of Mozambique and the port city of Sofala in the early 16th century. Vasco da Gama having visited Mombasa in 1498 was then successful in reaching India thereby permitting the Portuguese to trade with the Far East directly by sea, thus challenging older trading networks of mixed land and sea routes, such as the spice trade routes that used the Persian Gulf, Red Sea and caravans to reach the eastern Mediterranean. The Republic of Venice had gained control over much of the trade routes between Europe and Asia. After traditional land routes to India had been closed by the Ottoman Turks, Portugal hoped to use the sea route pioneered by da Gama to break the Venetian trading monopoly. Initially, Portuguese rule in East Africa focused mainly on a coastal strip centred in Mombasa. With voyages led by Vasco da Gama, Francisco de Almeida and Afonso de Albuquerque, the Portuguese dominated much of southeast Africa's coast, including Sofala and Kilwa, by 1515. Their main goal was to dominate trade with India. As the Portuguese settled along the coast, they made their way into the hinterland as (backwoodsmen). These lived alongside Swahili traders and even took up service among Shona kings as interpreters and political advisors. One such managed to travel through almost all the Shona kingdoms, including the Mutapa Empire's (Mwenemutapa) metropolitan district, between 1512 and 1516.