Bulgaria, situated in the eastern Balkans, has been undergoing a slow and painful transition to a market economy since the end of Communist rule.
A predominantly Slavic-speaking, Orthodox Christian country, Bulgaria was the birthplace of the Cyrillic alphabet, which was created there towards the end of the 9th century AD.
It was long influenced by Byzantine culture then was part of the Ottoman Empire for 500 years before gaining its independence in the 19th century.
After World War II it became a satellite of the Soviet Union, but is now a member country of the EU and NATO.
Its transition to democracy and a market economy after the collapse of communism has not been easy and the country is striving to boost low standards of living.
At a glance
- Politics: Inconclusive elections in May 2013 resulted in the formation of a government of technocrats
- Economy: Bulgaria is one of the EU's poorest countries. Organised crime and corruption have deterred investors and hindered growth
- International: Bulgaria joined Nato in 2004 and the EU in 2007. It is not part of the EU's passport-free Schengen zone
Country profiles compiled by BBC Monitoring
Throughout the early 1990s Bulgaria was wracked by political instability and strikes. The former communists were a powerful influence. Although the end of the decade was more stable, there was little tangible progress with economic reform.
Under Bulgaria's former king, Simeon II, who was prime minister between 2001 and 2005, the country pressed ahead with market reforms designed to meet EU economic targets.
It achieved growth, saw unemployment fall from highs of nearly 20% and inflation come under control, but incomes and living standards remained low.EU membership
Bulgaria was not among the countries invited to join the EU in 2004. However, it signed an EU accession treaty in April 2005 and joined in January 2007.
EU officials set tough entry requirements, reflecting their concerns about corruption and organised crime. After a series of reports found that the Bulgarian government had failed to tackle these issues effectively, the EU announced in July 2008 that it was suspending aid worth hundreds of millions of euros.
In September 2010, the EU again called on Bulgaria to take urgent action to tackle crime and corruption, and later in the year France and Germany announced that they would block Bulgaria from joining the Schengen passport-free zone until the country had made "irreversible progress" in this area.
Another cause of friction has been the Kozloduy nuclear power plant, which supplies over a third of Bulgaria's electricity.
Amid concerns over the safety of communist-era nuclear facilities, four of Kozloduy's six reactors were shut down as a price for Bulgaria's EU membership, two of them closing just minutes before the country joined the EU.
In a bid to offset the loss of production at Kozloduy and restore its position as a major power exporter in the Balkans, Bulgaria revived plans for a second nuclear power plant, though these were later put on hold.
Bulgaria is also involved in two rival gas pipeline projects: Russia's South Stream pipeline and the EU-backed Nabucco pipeline.Political crisis
Spiralling utilities bills brought down the conservative government of Boiko Borisov in February 2013. Widespread public perception that high fuel costs were the direct result of a too-cosy relationship between the government and foreign-owned privatised monopolies sparked violent protests.
Although Mr Borisov's GERB party won the most seats in the election in May, it failed to achieve a majority and a government of technocrats backed by the Socialists was subsequently formed. However, the protests against official corruption that toppled the Borisov government appeared to intensify under the new government led by Plamen Oresharski.