Yulia Tymoshenko, 53, one of Ukraine's top presidential candidates, has been the country's most influential woman for many years, enjoying great powers both in the government and the opposition at different times.

Once a natural-gas magnate which earned her nickname Ukraine's Gas Princess, Tymoshenko became the country's prime minister following the 2004 Orange Revolution, an anti-government uprising that removed the post-Soviet establishment, as her impassioned speeches resonated with thousands of Ukrainian voters.

From 2010 up until her conviction of corrupt practices in October 2011, she was Ukraine's top opposition leader.

Tymoshenko lost national elections to President Viktor Yanukovich in 2010.

"I will continue my fight for Ukraine, for its European future," she said during a short break before the verdict issued on October 11, 2011.

"Nobody ... can humiliate my honest name. I have worked and will continue to work for Ukraine's sake."

Considered glamorous and feisty by her supporters, she spent three years in prison for "abusing" her power by signing a gas deal with Russia while she was the PM in 2009.

Her release was made possible by a vote in parliament that changed the criminal code after popular uprising toppled President Viktor Yanukovich in February 2014.

The prison time has heightened her Joan of Arc-like status among her supporters, while detractors consider her corrupt and self-serving.

During her presidential election campaign, she focused on the patriotic sentiments of the Ukrainian public, promising to regain control over Crimea that was annexed by Russia in March 2014.

"The Kremlin today has declared war. Not on Crimea. Not on Ukraine. But on the whole world," Tymoshenko told Al Jazeera.

Early years

Born in 1960, in Russian-speaking Dnipropetrovsk in eastern Ukraine, Tymoshenko studied at the local university, married while still a teenage student and had a daughter in 1980.

Taking advantage of an entrepreneurial climate in the Soviet Union under Mikhail Gorbachev, Tymoshenko's first taste of self-made money came from a video rental store she set up in the 1980s with her husband.

In the 1990s, Tymoshenko became known as the "gas princess", when she headed Unified Energy Systems, a company that imported Russian gas into Ukraine.

Her career in the gas industry is believed to have amassed her a fortune.

She entered parliament in 1996 and was made a deputy prime minister in charge of the energy sector in 2000 by Viktor Yushchenko, the new premier.

But in 2001 she fell victim to political intrigues, spending several weeks in jail accused of forging customs documents and smuggling gas - charges of which she was subsequently cleared.

Orange Revolution

On leaving prison, she changed her image from brunette to blonde, wearing designer clothing and adopting her trademark peasant-style braid.

Her stylist later told media that the folksy look was designed to distance herself from an association with wealth and to emphasise a national Ukrainian identity.

Tymoshenko shot onto the world stage with her impassioned speeches in the 2004 mass protests against the sleaze of a post-Soviet establishment, in what became known as the Orange Revolution.

Viktor Yushchenko, who swept to power following the 2004 election, appointed her as his first prime minister in 2005, but their relations became quickly strained and she was dismissed eight months later.

Tymoshenko won her second term as prime minister in December 2007, after convincing Yushchenko to dissolve parliament after the Party of Regions and left-wing parties formed a coalition.

Her policies included compensation for depositors who lost Soviet-era savings, price controls on food and medicines to bring inflation down, calls for a review of murky privatisations and high social spending.

Source: Al Jazeera and agencies