centres defended by large African slave armies known as Chikunda. Historically within Mozambique there was slavery. Human beings were bought and sold by African tribal chiefs, Arab traders, and Portuguese and French traders as well. Many Mozambican slaves were supplied by tribal chiefs who raided warring tribes and sold their captives to the prazeiros.
Although Portuguese influence gradually expanded, its power was limited and exercised through individual settlers and officials who were granted extensive autonomy. The Portuguese were able to wrest much of the coastal trade from Arabs between 1500 and 1700, but, with the Arab seizure of Portugal's key foothold at Fort Jesus on Mombasa Island (now in Kenya) in 1698, the pendulum began to swing in the other direction. As a result, investment lagged while Lisbon devoted itself to the more lucrative trade with India and the Far East and to the colonisation of Brazil. During these wars, the Mazrui and Omani Arabs reclaimed much of the Indian Ocean trade, forcing the Portuguese to retreat south. Many prazos had declined by the mid-19th century, but several of them survived. During the 19th century other European powers, particularly the British (British South Africa Company) and the French (Madagascar), became increasingly involved in the trade and politics of the region around the Portuguese East African territories.
By the early 20th century the Portuguese had shifted the administration of much of Mozambique to large private companies, like the Mozambique Company, the Zambezia Company and the Niassa Company, controlled and financed mostly by the British, which established railroad lines to neighbouring countries. Although slavery had been legally abolished in Mozambique, at the end of the 19th century the Chartered companies enacted a forced labor policy and supplied cheap—often forced—African labour to the mines and plantations of the nearby British colonies and South Africa. The Zambezia
