Who Is Dmitry Medvedev, Russia's Permanent Prime Minister?

Vladimir Putin, sworn in on Monday for another six years as Russian president, has nominated Dmitry Medvedev again to be his prime minister.

Here's an introduction to the 52-year-old Medvedev, a long-time Putin ally who has already served as prime minister since 2012.

— Medvedev, like Putin, was born in Soviet Leningrad, now called St Petersburg. A law graduate, both he and Putin were close to the late Anatoly Sobchak, mayor of the city from 1991-1996. Sobchak is often spoken of as Putin's political mentor.

— Medvedev worked with Putin in the early 1990s in St Petersburg city hall where Putin headed the Committee for Foreign Affairs. Medvedev then worked as a legal affairs director at a big timber firm.

— Putin, on becoming prime minister in 1999, appointed Medvedev to a senior position in Moscow. When an ailing Boris Yeltsin named Putin acting president, Putin made Medvedev deputy head of his presidential administration. Medvedev went on to successfully run Putin's first presidential election campaign.

— Medvedev then held senior management oversight roles at gas giant Gazprom and did a stint as Putin's chief-of-staff before taking on the role of First Deputy Prime Minister, where he was responsible for implementing big national projects.

— Putin hit a problem in 2008. He had served two consecutive presidential terms and was barred by the constitution from serving a third. Putin solved the puzzle by naming Medvedev as his handpicked presidential successor and by becoming prime minister himself instead. The ruling tandem lasted from 2008-2012.

— Medvedev as president cultivated an image as a more pro-Western and liberal figure than Putin and styled himself a crusading anti-corruption campaigner. For a while, some Russians and foreign leaders thought the country was really changing course and that Medvedev had genuine autonomy. That turned out to be short-lived. Putin returned to the presidency in 2012 and made Medvedev his prime minister in what critics said was a cynical job swap.

— Medvedev likes to swim every day and train with weights. A video of the two men doing a morning workout together went viral on the Internet in 2015. A video of Medvedev awkwardly dancing to a 1990s pop hit caused similar excitement in 2011, drawing mockery in some quarters.

— Medvedev, who is married and has a son, is a keen amateur photographer and is well known for his love of gadgets and smartphones. He is also known as a fan of British hard rock music from the 1970s.

— Critics accuse Medvedev, whose surname is derived from the Russian word for bear, of being too laid back and not tough enough, and he has been spotted asleep at high profile events. However, Putin has publicly stayed loyal to Medvedev, who is thought to be one of the president's most trusted allies.

— Opposition leader and Kremlin critic Alexei Navalny last year accused Medvedev of amassing a secret property empire through an opaque corruption scheme. An online video detailing the allegations has since garnered more than 27 million views. Medvedev has dismissed the allegations as politically motivated nonsense.