Yulia Tymoshenko was a key figure of the Orange Revolution, as the massive protests in Ukraine in 2004 were dubbed. The results of the presidential elections, in favour of Viktor Yanukovich, were denounced as faulty, and eventually a second vote was held.
This former businesswoman in the gas industry officially became Prime Minister in February 2005. She was the third most powerful woman in the world, according to Forbes magazine. But her Government lasted for less than eight months.
Tymoshenko was once again elected as Prime Minister in December 2007. Her government was marked by a strong rivalry with President Yuschenko, her former ally in the Orange Revolution.
In 2010, she ran an unsuccessful presidential campaign. Yanukovich won in a close race, She alleged that fraud had been committed again.
That is when her problems with the Ukrainian justice system began.
Tymoshenko was convicted on charges she had abused her power as prime minister when she brokered a gas deal with Russia in 2009. She was sentenced last October to seven years in prison.
The Yanukovich government says the deal ran counter to national interests.
Tymoshenko faces more time in court, on charges of tax evasion and attempted embezzlement which carry sentences of up to 12 years.
The hearings started in her absence due to her health problems. She suffers from spinal disc herniation. She has always refused any kind of medical treatment proposed by the Government.
Tymoshenko says these cases are personal revenge campaigns and part of repression in Ukraine.
Her conviction drew condemnation from the West.