Syrian President Bashar al-Assad is expected to attend an Arab summit in Saudi Arabia on Friday, ending his isolation by states that shunned him during a civil war that has killed more than 350,000 people. Here are some key moments in the war and Assad's emergence from isolation:
* March 2011 - Protests inspired by the Arab Spring erupt against Assad's rule in Deraa before spreading across Syria. Security forces respond with arrests and shootings.
* Aug. 2011 - U.S. President Barack Obama says Assad has lost legitimacy to rule and should surrender power.
* Nov. 2011 - The Arab League suspends Syria and urges its army to stop killing civilians. More than 3,500 people have been killed in seven months of violence, the United Nations says.
* June 2012 - World powers meeting in Geneva agree on the need for a political transition but divisions on how to achieve it will foil years of U.N.-sponsored peace efforts.
* July 2012 - Assad launches air raids on towns and cities that had rebelled against him. Once peaceful protesters now carry arms. Thousands are killed.
* Aug. 2012 - President Obama warns Assad not to cross a "red line" by using chemical or biological weapons, suggesting that such action would prompt the United States to consider a military response.
* March 2013 - Syrian opposition leaders take Syria's seat at an Arab League summit in Doha after Qatar’s emir asks his fellow Arab leaders to invite them to represent the country.
* May 2013 - The Iran-backed Lebanese group Hezbollah spearheads a government offensive that retakes the rebel-held town of Qusair, the rebels' biggest defeat since the war began.
Qatar and Saudi Arabia support insurgents. The U.S. Central Intelligence Agency establishes a programme with regional allies to funnel support to rebels.
* Aug. 2013 - A gas attack on rebel-held Eastern Ghouta on the Damascus outskirts kills hundreds of civilians but prompts no U.S. military action. Syria denies using chemical weapons.
* Jan. 2014 - An al Qaeda splinter group seizes Raqqa before grabbing territory across Syria and Iraq, declaring a caliphate and renaming itself Islamic State.
* Sept. 2014 - Washington builds an anti-Islamic State coalition and starts air strikes, helping Kurdish forces turn the jihadist tide but creating friction with ally Turkey.
* Sept. 2015 - Russia joins the war on Assad's side, deploying war planes that bomb rebel-held areas - a turning point in the conflict.
* Aug. 2016 - Alarmed by Kurdish advances in northern Syria, Turkey launches an incursion with allied rebels.
* Dec. 2016 - Syria's army and its allies defeat rebels in their biggest urban base of Aleppo after months of siege and bombardment.
* April 2017 - The United States launches a cruise missile attack on a government airbase near Homs after a poison gas attack on rebel-held Khan Sheikhoun kills scores of people.
* Nov. 2017 - U.S.-backed, Kurdish-led forces defeat Islamic State in Raqqa before driving the jihadists from their last town in Syria, Baghouz, in 2019.
* April 2018 - After years of siege, rebel-held Eastern Ghouta succumbs in a Russian-backed campaign. The final days of the fighting are marked by a chlorine gas attack that kills 43 people. Washington and its allies fire missiles at Syria.
Syria denies any role.
Russian-backed government forces go on to seize other insurgent enclaves including Deraa in June.
* March 2019 - Saudi Arabia says it is too early to restore diplomatic ties with Syria or reinstate it to the Arab League without progress on a political process to end the war.
* April-Dec. 2019 - Russian-backed forces start a campaign in the northwest.
* March 2022 - Assad visits the United Arab Emirates and meets its leaders, his first trip to an Arab state since 2011. Washington objects, calling it an apparent attempt to legitimize Assad.
* Dec. 2022 - The Turkish and Syrian governments hold their highest-level talks in years when their defence ministers meet in Moscow. Turkish President Tayyip Erdogan says he could meet Assad. Assad says he will only meet Erdogan when Turkey is ready to withdraw forces from Syria.
* Feb. 2023 - A deadly earthquake prompts an outpouring of Arab support for Syria. The foreign ministers of Egypt and Jordan visit Damascus for the first time since the war began.
* April 2023 - Assad receives Saudi Foreign Minister Prince Faisal bin Farhan in Damascus.
* May 2023 - The Arab League readmits Syria.
