Timeline: Sao Tome and Principe

A chronology of key events:

16th century - Sao Tome colonised by the Portuguese, who bring in slaves to work sugar plantations. Becomes important staging post for slave trade.

Colonial heritage is evident in the capital Sao Tome town population: 52,000 2002: Drenched in Sao Tome and Principe

1800s - Cocoa introduced. Sao Tome develops into one of world's main cocoa producers.

1951 - Becomes overseas province of Portugal.

1960 - Formation of nationalist group which later becomes the socialist oriented Movement for the Liberation of Sao Tome and Principe (MLSTP).

1974 - Military coup in Portugal. Portuguese government recognises islands' right to independence, acknowledges MLSTP as sole representative in negotiations. Unrest followed by exodus of Portuguese.

Independence

1975 12 July - Independence, with Manuel Pinto da Costa (MLSTP) as president; and Miguel Trovoada as prime minister. Plantations nationalised, strong ties built up with communist countries.

San Sebastian fort, home of the national museum

1978 - Government announces suppression of coup attempt, brings in Angolan troops for support.

1979 - Trovoada arrested, accused of complicity in coup attempt. He is released and goes into exile in 1981.

1980s - Government scales down links with communist world as economy deteriorates. Declares itself nonaligned, seeks Western support for recovery plans.

1988 - Coup attempt.

1990 - New constitution allows opposition parties, provides for multi-party elections and restricts president to two five-year terms. Trovoada returns from exile.

Multiparty elections

1991 - First multiparty elections. Renamed MLSTP-PSD loses majority. Transitional government installed, pending presidential elections, subsequently won by independent candidate Trovoada.

1992 - Popular unrest sparked by austerity measures.

1994 - MLSTP-PSD regains power. Parliament grants Principe local autonomy.

Miguel Trovoada: Won first multi-party elections, survived 1995 coup

1995 - Trovoada toppled and detained in bloodless coup by soldiers but is reinstated within days after pressure from donor countries.

1996 - Trovoada re-elected president. Popular protests over economic hardships.

1997 - Unrest over economic conditions.

Sao Tome establishes formal diplomatic relations with Taiwan at Trovoada's behest. The move is condemned by the government. China retaliates by suspending ties.

1998 - MLSTP-PSD wins general elections, Guilherme Posser da Costa appointed prime minister.

2000 - Civil servants strike to press for higher pay. Officials say country's external debt in 1998 amounted to US $270 million, more than five times the country's annual gross domestic product of around US $50 million.

De Menezes sworn in

2001 - Businessman Fradique de Menezes is declared the winner in the presidential election in July and is sworn into office in early September.

2002 March - MLSTP narrowly wins parliamentary elections. De Menezes appoints Gabriel Costa as prime minister and both main political parties agree to form broad-based government.

2002 August - President De Menezes announces plans for a US naval base in the country, which would aim to protect Sao Tome's oil interests.

2003 COUP Deal allowed for return of president and amnesty for junta 2003: The Sao Tome coup-makers 2003: Amnesty for Sao Tome coup

2002 October - President De Menezes names new government with Maria das Neves as premier. It replaces administration led by former prime minister Gabriel Costa, which was dismissed by De Menezes in September.

2003 16 July - Military coup topples the government. President De Menezes, in Nigeria at the time, returns to Sao Tome a week later after an agreement is struck with the junta. A general amnesty is given to the coup leaders.

2003 October - Oil companies bid for offshore oil blocs controlled by Sao Tome and Nigeria. Bids are expected to generate hundreds of millions of dollars in licence money for Sao Tome.

2004 March - Row between president, prime minister over control of oil deals threatens to topple government. Four cabinet ministers are replaced.

2004 September - President De Menezes sacks the prime minister and government after a series of corruption scandals. A new prime minister is sworn in.

2004 December - Parliament approves oil law designed to protect revenues from corruption.

2005 February - Sao Tome - jointly with Nigeria - signs its first offshore oil exploration and production-sharing agreement with international oil firms.

2005 June - Prime minister and government resign. Head of the central bank Maria do Carmo Silveira becomes the new premier.

2006 March - Protests against poor living conditions disrupt parliamentary elections in some constituencies, delaying announcement of results. The president's Democratic Movement of Forces for Change (MDFM) is declared winner, taking 23 of the 55 seats in parliament.

2007 March - World Bank, IMF forgive $360 million in debt owed by Sao Tome. This represents about 90% of the country's foreign debt.

Nigeria and Sao Tome agree to establish a joint military commission to protect their common oil interests in the Gulf of Guinea.

2008 February - Opposition leader Patrice Trovoada becomes prime minister.

2008 May - Prime Minister Patrice Trovoada dismissed after parliament passes vote of no confidence against coalition government.

2008 June - Rafael Branco, head of Sao Tome's second largest party, sworn in as prime minister at head of a new governing coalition.