President-day São Tomé is discovered by Portugal in 1471 and colonized since 1493 by Portuguese settlers, followed in 1500 by the coloniation of Príncipe. In 1522 Portugal takes officially posession of the island of São Tomé and establishes a Portuguese crown colony. This is followed by the acquisition of Príncipe in 1558. Both islands form since 1753 the crown colony of São Tomé and Príncipe. Slavery is abolished in 1876, but the practice of forced paid labor continues. The colony is restyled as an overseas province in 1951. Shortly later, in 1953, riots break out in which several hundred African laborers are killed in a clash with their Portuguese rulers (the "Batepa Massacre"). By the late 1950s, the Movimiento de Libertaçao de São Tomé e Príncipe (Liberation Movement of São Tomé e Príncipe, MLSTP) is formed, which eventually establishes its base in nearby Gabon.

After the revolution in Portugal and a period of transitional government, São Tomé and Príncipe achieve independence as the Democratic Republic of São Tomé and Príncipe in 1975. The republic becomes a dictatorship under the MLSTP of president Manuel Pinto da Costa. In 1990 the country embraces democratic reform and changes to the constitution, leading to ninviolent, free and transparent elections in 1991. The MLSTP adds to it name Partido Social Democrata (Social Democratic Party). The conservative Partido de Convergência Democrática-Grupa de Reflexão (PCD) topples the MLSTP to take a majority of seats in parliament. Miguel dos Anjos da Cunha Lisboa Trovoada, a former prime minister who was in exile since 1986, is elected president as an non-partisan candidate. Norberto José d'Alva Costa Alegre becomes prime minister. The PCD loses the 1994 elections and the MLSTP wins a plurality of seats. Carlos da Graça becomes prime minister. A military coup in 1995 fails. Da Graça is succeeded by Armindo Vaz d'Almeida.

Trovoado is re-elected in 1996 as the candidate of the Acçao Democrática Independente (Independent Democratic Action, ADI). Raul Bragança Neto succeeds Vaz d'Almeida in 1996 as prime minister. The MLSTP gains an outright majority of seats in the 1998 elections. The MLSTP replaces Bragança in 1999 by Guilherme Posser de Costa. In 2001 the candidate of the ADI, Fradique Melo Bandeira de Menezes, is elected president. The 2002 parliamentary elections lead to a coalition government after no party gains a majority of seats. This coalition of MLSTP and PCD is presided by Gabriel Arcanjo Ferreira de Costa and later in 2002 by Maria das Neves Ceita Baptista de Sousa of the MLSTP. She forms a coalition with the party of De Menezes, the new Movimento Democrático das Forças da Mudança (Forces for Change Democratic Movement, MDFM). She is fired by the president in 2004, who requests the MLSTP to propose a new prime minister.