Mozambique is a republic in Africa, bounded north by Zambia, Malawi, and Tanzania, west by Zimbabwe, south-west by South Africa and Swaziland, with access to the Indian Ocean in the east. Evidence of human presence dates back 100,000 years. Beginning in the first century AD, Bantu speaking people migrated from central Africa into the region. Trading settlements were established by Arab and Persian merchants along the coast at Sofala, Angoche, Queliamane, and Mozambique Island during the fifteenth century. Portuguese explorer Vasco da Gama arrived in 1498, which led to the establishment of trading posts at Mozambique Island and Sofala by 1506, and the opening of the Mozambique interior to prospectors and merchants over the next century. Mozambique was administered as part of Portuguese India until 1752, and in 1951 the country became an overseas province of Portugal. Following a decade of guerilla warfare, Mozambique declared independence in 1975. The capital and largest city is Maputo (formerly known as Lourenço Marques). The estimated population of Mozambique in 2011 was 23,929,708.