Sao Tome and Principe, once a leading cocoa producer, consists of two islands of volcanic origin and a number of smaller islets lying off the coast of Africa.
From the late 1400s Portugal began settling convicts on Sao Tome and establishing sugar plantations with the help of slaves from the mainland. The island was also important in the transshipment of slaves.
The colony's aspirations for independence were recognised after the 1974 coup in Portugal and at first the Movement for the Liberation of Sao Tome and Principe was the country's sole political party. However, the 1990 constitution created a multi-party democracy.
The island of Principe assumed autonomy in 1995.
The country hopes to reduce its dependence on donors and cocoa exports by exploiting offshore oil.
The Democratic Republic of Sao Tome and Principe
Capital: Sao Tome
Area 1,001 sq km (386 sq miles)
Major language Portuguese
Life expectancy 64 years (men), 66 years (women)
President: Evaristo Carvalho
Evaristo Carvalho - a former prime minister - won the run-off presidential election in August 2016.
Vice president of the ruling ADI party, Mr Carvalho was guaranteed victory in the run-off after his rival, incumbent President Pinto da Costa, dropped out alleging irregularities in the first round.
Mr Carvalho, 75 at the time of being elected, was prime minister in 1994 and again in 2001-2002, and has also served as president of the national assembly and defence minister.
Sao Tome has a tradition of premiers and presidents from opposing camps governing together peacefully. Now, however, both top jobs are held by the ADI party.
The president has an arbitrating role in government but no executive powers, leaving the prime minister in the dominant position.
Prime minister: Patrice Emery Trovoada
Patrice Emery Trovoada was appointed prime minister by President Manuel Pinto da Costa in 2014 following elections which his Independent Democratic Action (ADI) party won.
Mr Trovoada first served as prime minister in 2008 by his government fell after a vote of no confidence. He began a second term as prime minister in August 2010, and was again unseated following a vote of no-confidence in December 2012. He is the son of former President Miguel Trovoada.
Freedom of expression, guaranteed by the constitution, is also respected in practice.
The state runs the only radio and TV stations but no law forbids private broadcasting.
Some key dates in Sao Tome's history:
16th century - Sao Tome colonised by the Portuguese, who bring in slaves to work sugar plantations. Becomes important staging post for slave trade.
1800s - Cocoa introduced. Sao Tome develops into one of world's main cocoa producers.
1974 - Military coup in Portugal. Portuguese government recognises islands' right to independence.
1975 - Independence, with Manuel Pinto da Costa as president. Plantations nationalised, strong ties built up with communist countries.
1990 - New constitution allows opposition parties.