President Lech Kaczynski and his wife Maria were killed, along with a number of other senior Polish political, military and cultural figures, when their plane crashed as it prepared to land in western Russia on Saturday 10 April 2010. Here are brief profiles of the president and other key figures.
PRESIDENT LECH KACZYNSKI
Lech and Maria Kaczynski married in 1978 and had one daughter
Lech Kaczynski aroused controversy in Poland and on the world stage. His right-wing stance on many issues found ready reception among many Poles, especially traditionalist and rural voters.
As mayor of Warsaw, he twice banned gay parades and spoke in support of reintroducing the death penalty.
He was elected as Poland's president in 2005 as candidate of the Law and Justice Party.
He and his twin brother Jaroslaw jointly governed Poland from July 2006 to November 2007 when Jaroslaw was prime minister.
Mr Kaczynski was born in 1949 and got his start in politics in the anti-government movement in the late 1970s.
The twins were key players in securing the victory of the Solidarity leader Lech Walesa in the 1990 presidential election, the first of the post-Communist era, but they later fell out with Mr Walesa.
ALEKSANDER SZCZYGLO, NATIONAL SECURITY CHIEF
Aleksander Szczyglo (R) was a long-time defence official
Mr Szczyglo, 46, was chief of the National Security Office (or BBN), the government agency in charge of national security, answering to the president.
In 2007 he served as defence minister in the government of Jaroslaw Kaczynski.
He was first elected to parliament in 2001 as a candidate of the Law and Justice Party and re-elected in 2005.
SLAWOMIR SKRZYPEK, GOVERNOR, NATIONAL BANK OF POLAND
Mr Skrzypek had recently clashed with the cabinet
Mr Skrzypek took the reins of Poland's central bank in January 2007, after running the country's largest bank, PKO Bank Polski.
In taking over the central bank he was criticised for his lack of relevant experience. He had previously also worked for the state railway company and as the deputy to Lech Kaczynski when he was mayor of Warsaw.
He had recently clashed with the government over the rules for calculating the central bank's profit, which the government wanted to use to reduce the budget deficit.
The 46-year-old was married with three children.
JERZY SZMAJDINSKI, DEPUTY SPEAKER OF THE LOWER HOUSE
He was born on 9 April 1952. He was a member of Poland's Communist Party and after the fall of the Communist government joined the party that eventually became the Democratic Left Alliance (or SLD).
He was elected to parliament in 1990 and subsequently re-elected, serving on the National Defence Committee.
Mr Szmajdzinski was defence minister from 2001 to 2005, under prime ministers Leszek Miller and Marek Belka.
He was nominated to be the SLD's candidate for the presidency in the election scheduled for October 2010.
FRANCISZEK GAGOR, CHIEF OF THE GENERAL STAFF
Poland's armed forces have close contact with the US military
General Gagor had been head of Poland's military since 2006. He was born on 8 September 1951.
He was a career officer who later took an active part with United Nations peacekeeping operations.
He was a senior officer on Poland's contingent in the first Gulf War in 1991 and then helped negotiate Poland's entry to Nato. He was married with two children.
RYSZARD KACZOROWSKI, FORMER PRESIDENT-IN-EXILE
Ryszard Kaczorowski was well-loved among exiles in London
Faced with the 1939 Nazi invasion on one side, and the Soviets on the other, Mr Kaczorowski, 90, became a leader of the underground Polish resistance. Arrested by Soviet secret police and sentenced to death, he was later released as part of a deal between the Soviet Union and the Polish government-in-exile, and went on to fight with the Polish armed forces against the Nazis.
A Polish government-in-exile continued to work during the war - first in France and then in Britain - and then after the war, in opposition to the Communist government.
From 1989-90, Mr Kaczorowski, an accountant who lived in Harrow in north London, served as the last president-in-exile.
In December 1990, he passed on the insignia of the presidency to the first democratically elected president, Lech Walesa, in a high-profile ceremony.
PRZEMYSLAW GOSIEWSKI, DEPUTY HEAD, LAW AND JUSTICE PARTY
Born on 12 May 1964. He was elected to parliament with the Law and Justice Party in 2001 and re-elected in 2005.
He was a cabinet minister in 2006 and in 2007 served as the deputy prime minister to Jaroslaw Kaczynski.
Anna Walentynowicz was a crane driver and trade union activist at the Gdansk shipyard whose dismissal in 1980 sparked the strike that led to the creation of the Solidarity movement.
She was born in 1929 and orphaned during WWII. She played herself in several movies that depicted the events of the Gdansk strike.