A timeline of the Tymoshenko case:

- March 2010: Tymoshenko resigns after a vote of no confidence in parliament. Deputies accuse her of abuse of power and signing an overpriced deal to buy natural gas from Russia.

- June 2011: She goes on trial in Kiev. Supporters and opponents brawl in the courtroom and on the streets.

- October 2011: The court sentences her to seven years in prison. There is international condemnation of the verdict. The European Union calls off a meeting with Tymoshenko arch-rival President Viktor Yanukovych.

- December 2011: Tymoshenko is moved to a women’s prison in Kharkiv, 450 kilometres east of Kiev.

- February 2012: The opposition leader, complaining of severe back pain, is examined by German and Canadian doctors. They diagnose a slipped disc.

- April 2012: Tymoshenko begins a hunger strike in protest at her treatment by the Kharkiv prison staff.

- May 2012: A planned meeting of European presidents in Yalta is called off after several make clear that they will not be attending because of the Tymoshenko issue.

- June 2012: The Euro 2012 football tournament begins in Poland and Ukraine. Some European Union politicians decline to attend games in Ukraine.

- July 2012: The European Court of Human Rights in Strasbourg rules that Ukraine violated the rights of a jailed Tymoshenko ally, former interior minister Yuri Lutsenko, and orders Ukraine to pay damages.

- August 2012: The same European Court hears Tymoshenko’s complaint about her detention and prison conditions.

- January 2013: Tymoshenko is named a suspect in the long-dormant 1996 contract murder case of Ukrainian politician and businessman Yvhen Scherban.

- February 2013: EU leaders give Yanukovych a May deadline to show “tangible progress” on democratic reforms.

- April 2013: Yanukoych pardons Lutsenko, but says it is too early to consider pardoning Timoshenko.

- April 2013: The European Court of Human Rights rules that Tymoshenko’s pre-trial detention was unlawful but rejects her claim that she is being denied adequate health care.

- November 2013: Draft legislation that would have allowed Tymoshenko to leave Ukraine for treatment in Germany fails to get enough votes in parliament. EU politicans had made her release a key demand for an association agreement with Ukraine.

- November 2013 - February 2014 - Yanukovych scraps EU association agreement and takes up closer relations with Russia, triggering massive anti-government demonstrations triggered. In recent violence related to the conflict, at least 77 people - mainly opposition supporters - were killed.

- February 22, 2014: Ukraine’s parliament votes for Tymoshenko’s immediate release. Several hours later, Tymoshenko leaves the prison hospital where she was being treated for back problems headed for Kiev.