June 2005 - In a stunning upset, Mahmoud Ahmadinejad, the hitherto little-known mayor of Tehran, defeats former president Akbar Hashemi Rafsanjani in a run-off vote for the presidency.
February-March 2008 - Hardline state vetting bodies bar hundreds of reformists from running in the March 14 parliamentary election, in which conservatives win a majority. Western powers, embroiled in a standoff with Tehran over its disputed nuclear program, condemn the election as unfair.
March 2008 - UN Security Council adopts third sanctions resolution targeting Iran's nuclear program.
January 2009 - After three decades of mutual mistrust, new U.S. President Barack Obama offers a new beginning of engagement with Tehran if it "unclenches its fist".
March 2009 - Obama issues a videotaped appeal to Iran offering a "new beginning" of diplomatic engagement. A day later, clerical Supreme Leader Ayatollah Ali Khamenei says Obama's offer is just a "slogan", but pledges Tehran will respond to any real policy shift by Washington, adding: "You change, our behavior will change."
April 2009 - Ahmadinejad accuses Israel of mass murder and ethnic cleansing against the Palestinians, two days after his denunciation of the Jewish state as racist prompted a walk-out from a United Nations meeting on race.
June 2009 - Ahmadinejad wins June 12 election, defeating reformist challenger Mir Hossein Mousavi. Thousands of people, protesting at alleged election fraud, clash with police. Mousavi calls the result a "dangerous charade". Scores of people are killed and thousands arrested. Years of repression follow.
August 2009 - Khamenei formally approves Ahmadinejad's second term on Aug. 3. He is sworn in two days later.
October 2009 - UN nuclear inspectors gain access to a previously secret, underground uranium enrichment plant near the Shi'ite Muslim holy city of Qom.
February 2010 - An International Atomic Energy Agency report suggests for the first time that the Islamic Republic has been actively pursuing the means to develop a nuclear weapon.
June 2010 - The United Nations and U.S. Congress approve new unilateral sanctions aimed at squeezing Iran's energy and banking sectors. In July, the European Union imposes tighter sanctions on Iran to block investment in its oil and natural gas sectors and curtail its refining.
November 2011 - Iranians storm the British Embassy in Tehran in a protest against sanctions imposed by Britain, which closes the mission and withdraws all diplomatic staff.
October 2012 - EU governments agree further sanctions against Iran's banking, shipping and industrial sectors, cranking up financial pressure on Tehran a few days after riots break out in Tehran in protest at the collapse of the rial currency. The rial has lost some two-thirds of its value against the dollar over the previous 15 months.
April 2013 - In two sets of talks held in Kazakhstan, six world powers and Iran fail again to end the deadlock in a decade-old dispute over Tehran's nuclear programme. Two months earlier Iran had defiantly announced that it was building about 3,000 advanced uranium-enrichment centrifuges.
May 2013 - Iran is pressing ahead with the construction of a heavy-water reactor Western experts say could offer it a second way of producing material - plutonium - for a nuclear bomb if it decides to develop one, an IAEA report shows.
Want to enjoy 'Zen' reading - with no ads and just the article? Subscribe todaySubscribe now