The islands of São Tomé and Príncipe were uninhabited when the Portuguese arrived sometime around 1470. The first Europeans to put ashore were João de Santarém and Pêro Escobar. Portuguese navigators explored the islands and decided that they would be good locations for bases to trade with the mainland.
The dates of European arrival are sometimes given as 21 December (St Thomas's Day) 1471, for São Tomé; and 17 January (St Antony's Day) 1472, for Príncipe, though other sources cite different years around that time. Príncipe was initially named Santo Antão ("Saint Anthony"), changing its name in 1502 to Ilha do Príncipe ("Prince's Island"), in reference to the Prince of Portugal to whom duties on the island's sugar crop were paid.
The first successful settlement of São Tomé was established in 1493 by Álvaro Caminha, who received the land as a grant from the crown. Príncipe was settled in 1500 under a similar arrangement. Attracting settlers proved difficult, however, and most of the earliest inhabitants were "undesirables" sent from Portugal, mostly Jews. In time, these settlers found the volcanic soil of the region suitable for agriculture, especially the growing of sugar.
By the late 1950s, when other emerging nations across the African continent demanded their independence, a small group of São Toméans had formed the Movement for the Liberation of São Tomé and Príncipe (MLSTP), which eventually established its base in nearby Gabon. Picking up momentum in the 1960s, events moved quickly after the overthrow of the Caetano dictatorship in Portugal in April 1974.
The new Portuguese regime was committed to the dissolution of its overseas colonies. In November 1974, their representatives met with the MLSTP in Algiers and worked out an agreement for the transfer of sovereignty. After a period of transitional government, São Tomé and Príncipe achieved independence on 12 July 1975, choosing as the first president the MLSTP Secretary General Manuel Pinto da Costa.