March 2011: First protests erupt, dozens killed. Government announces reforms, then resigns.
April, May 2011: Protests intensify and spread, hundreds killed. U.S. imposes sanctions on top leaders.
August, September 2011: Saudi Arabia, Kuwait and Bahrain withdraw ambassadors. U.S. imposes economic sanctions, EU bans Syrian oil imports.
October 2011: Russia, China veto a U.N. resolution condemning Syria.
November 2011: The Arab League suspends Syria's membership.
January 2012: Government releases 5,000 prisoners. Death toll soars past 7,000.
February 2012: Russia, China veto a second U.N. resolution condemning crackdown
March 2012: Former U.N. chief Kofi Annan holds talks in Syria. U.N. says death toll exceeds 9,000. Syria agrees to U.N.-backed peace plan.
April 2012: Syria says it will abide by a cease-fire on April 12, but violence continues. U.N. observers arrive.
May 2012: Syria holds parliamentary elections, violence continues, U.N.-Arab League envoy Kofi Annan appeals to Syrian President Bashar al-Assad to stop the violence.
June 2012: Western nations expel Syrian diplomats, Annan urges increased pressure on Syria.
July 2012: Red Cross expands areas of Syria it says are in civil war. Violence increases across the country.
August 2012: A day after Syrian warplanes attacked the rebel-controlled northern town of Azaz and a bombing near the U.N. observer headquarters in Damascus, the United Nations Security Council decided to end the U.N. monitoring mission in Syria when its mandate expires on August 19.
September 2012: Fighting intensifies in Aleppo and continues across the country. New U.N.-Arab League envoy, Lakhdar Brahimi, is expected to visit the country and meet with Assad.