(Reuters) - Here is a look at Russia's two leaders, President Dmitry Medvedev and Prime Minister Vladimir Putin. Russia holds a presidential election on Sunday that will likely swap their positions.
December 31, 1999 - Russian President Boris Yeltsin steps down, making Prime Minister Putin the acting president.
March 26, 2000 - Putin wins the presidential election with 53 percent of the vote.
December 10, 2007 - Putin presents long-time ally Medvedev as his preferred successor and says he will become prime minister and lead the largest party in parliament. Putin's support makes Medvedev's victory in the March 2 presidential election certain.
May 8, 2008 - Putin becomes prime minister a day after Medvedev's inauguration as president.
September 11, 2009 - Putin says he has not yet decided whether to run for president in 2012 when Medvedev's term ends, in comments timed a day after Medvedev published his vision for Russia's economic and political reform.
June 1, 2010 - Medvedev criticizes Putin's government for ignoring environmental problems and says he is ready to throw the weight of his presidency behind the issue.
June 17 - Putin steals the headlines from Medvedev by overseeing a major energy deal before the president hosted Russia's biggest international investors' event. The deal later collapsed.
December 16 - Putin says Mikhail Khodorkovsky belongs in jail and suggests that the imprisoned tycoon, whom he has compared to American gangster Al Capone, was behind a string of murders.
December 24 - Medvedev says neither he nor any other government official has the right to comment on the second trial of Khodorkovsky before the verdict is announced.
January 14, 2011 - Putin blesses BP's $16 billion share swap with state-controlled Rosneft. The deal later collapses after BP's partners in its TNK-BP Russian venture oppose the deal. Medvedev says in May that those who prepared the deal should have done proper due diligence.
March 21 - Medvedev appears to rebuke Putin for comparing Western calls for action on Libya with the crusades in the sharpest public difference between Russia's ruling tandem.
March 31 - Medvedev orders the removal of ministers from boards of state firms, a move that forces Putin ally Igor Sechin from his post as Rosneft chairman.
May 13 - Medvedev says Russia could face civil war or stagnation if too much power was concentrated in the hands of one man, an apparent jibe at Putin.
June 17 - Medvedev warns that Russia will face stagnation if it fails to modernize and, in veiled criticism of the political system under Putin, said it must avoid one-man rule.
June 20 - Medvedev indicates he and Putin would not compete for the presidency. "Competition between us could undermine the tasks and the aims that we have been realizing in recent years."
June 21 - Putin dismisses speculation of a rift with Medvedev, saying he and his protégé share a "joint program" for Russia's development.
June 23 - Putin says the government has not yet found the money to pay for a payroll tax cut proposed by Medvedev.
September 24 - At a conference of Putin's United Russia party, Putin and Medvedev lay out plans for Putin to return to the presidency and Medvedev to take his place as prime minister, though they leave unclear when the latter might occur.
October 17 - Putin suggests his plan to appoint Medvedev as prime minister following his own return to the Kremlin depends on the ruling party's performance in the parliamentary election.
December 4 - Parliamentary election is held at which the United Russia party win a majority, Medvedev led the party's ticket. The opposition says the election was rigged, sparking protests.
December 15 - Putin confirms he intends to appoint Medvedev as prime minister after the 2012 presidential election.
December 22 - Medvedev calls for sweeping reform of Russia's political system to try to appease protesters.
-- Shortly afterward, the Kremlin appoints Deputy Prime Minister Sergei Ivanov as presidential chief of staff, handing one of the most powerful jobs to a Putin ally. Vyacheslav Volodin, another Putin ally, becomes deputy chief of staff.
February 28, 2012 - Putin brushes off a reported plot to kill him as part of his daily burden as Russia's prime minister. The opposition reacts with skepticism, suggesting the timing of the announcement would attract sympathy before the election.
March 4 - Presidential election.
Reporting by David Cutler, London Editorial Reference Unit; Editing by Alison Williams