Left: Syrian President Hafez al-Assad (right) in 1967. Right: An ISIS fighter in Raqqa, Syria, in 2014Keystone-France/Gamma-Rapho/Getty; Stringer/Reuters
Hafez al-Assad seizes power in a coup within the Baath Party. He becomes president of Syria the following year.
Syria and the Soviet Union sign a treaty of friendship and cooperation.
In response to a Sunni rebellion in Hama, Assad’s military destroys the city and kills at least 20,000 people.
Assad dies. He is succeeded by his son Bashar, who many Syrians hope will be a reformer.
Syrian President Bashar al-Assad on a visit to Greece in December 2003 Yiorgos Karahalis/Reuters
Undersecretary of State John Bolton includes Syria in a list of countries “beyond the axis of evil” that are seeking weapons of mass destruction.
President George W. Bush imposes sanctions on Syria, asserting that it has ties to terrorism.
Tensions between the United States and Syria escalate after former Lebanese Prime Minister Rafik Hariri is assassinated by a truck bomb, allegedly with help from Assad’s regime.
A massive bomb killed Lebanon’s former prime minister Rafik Hariri in Beirut in February 2005. Mohamed Azakir/Reuters
The United States renews sanctions against Syria, saying that it seeks weapons of mass destruction.
Protests begin in Daraa after police torture teenagers who had painted anti-regime graffiti. As mass demonstrations spread, the Assad regime cracks down violently.
Military defectors create the Free Syrian Army, Syria’s first armed opposition group.
Assad sends troops into Hama and Deir Ezzor, killing hundreds of civilians.
President Barack Obama calls for Assad to step down.
Al Qaeda’s new Syrian affiliate, the Nusra Front, stages a suicide bombing in Damascus.
The United States begins sending “nonlethal” aid to Syrian rebels.
The United States, Russia, Turkey, Iraq, and other countries meet in Geneva to discuss a transition to a “democratic and pluralistic” Syria.
Obama warns Assad that using chemical weapons would cross a “red line,” triggering US military intervention.
The Islamic State of Iraq and Syria (ISIS) forms.
Hezbollah forces launch an offensive “to aid the Assad regime.”
Congressional intelligence committees approve CIA arms shipments to the Syrian opposition.
The Syrian government uses sarin in an attack on Ghouta, killing more than 1,400 people. The following month, Congress rejects Obama’s request to approve a military response.
The Syrian government agrees to hand over its chemical weapons stocks for destruction.
Kurdish parties establish the autonomous region of Rojava in northern Syria.
ISIS declares the creation of a caliphate across its territory in Syria and Iraq.
Congress authorizes the Pentagon to train and arm Syrian rebels. In what will become known as Operation Inherent Resolve, the United States and its coalition partners begin airstrikes against ISIS.
As the number of refugees tops 4 million, a photograph of a drowned Syrian toddler provokes international concern over the humanitarian crisis. After reaffirming its treaty with Syria, Russia officially joins the war, carrying out airstrikes and providing military aid to Assad.
A drowned Syrian boy lies on the shore of southern Turkey after a boat carrying refugees sank in September 2015. Nilufer Demir/AFP/Getty
As the Obama administration’s focus in Syria shifts toward ISIS, the Pentagon says special operations troops will be deployed “to fight in Syria and Iraq.”
Supported by Russian planes, the Syrian government retakes Aleppo, a major rebel stronghold.
President Donald Trump blocks Syrian refugees from entering the United States. (Fewer than 3,100 have been admitted since he took office.)
UN Ambassador Nikki Haley says the Trump administration’s “priority is no longer to sit there and focus on getting Assad out.”
Following another chemical attack by the Syrian government, Trump announces a missile strike.
Over Turkey’s objections, Trump approves a plan to arm Kurdish forces in Syria.
Trump ends the CIA program to support anti-Assad rebels.
After months of heavy coalition bombing and ground assaults by the US-backed Syrian Democratic Forces, ISIS is driven out of Raqqa, losing its self-proclaimed capital.
Pro-Syrian government forces, including Russian mercenaries, attack the US-held Conoco gas plant outside Deir Ezzor city. The Geneva peace process that opened in 2012 ends.
Turkey and the FSA seize Afrin, a Kurdish region in northwest Syria.
After a chemical attack in Douma, the United States, Britain, and France launch airstrikes against Syrian government targets.
Assad’s army recaptures part of southern Syria from rebel forces.
US military officials report that an SDF offensive has isolated the “last pocket of ISIS resistance” in eastern Syria.
Trump announces the withdrawal of all US troops from Syria. Defense Secretary James Mattis resigns in protest.
Former Defense Secretary James Mattis and President Donald Trump in October 2018 Leah Mills/Reuters
ISIS’s remaining fighters are trapped in shrinking enclaves. Trump says he should receive a Nobel Peace Prize for his efforts in Syria. “I stopped the slaughter of perhaps 3 million people,” he says. When members of Congress request that some troops stay in Syria, Trump writes back, “I agree 100%.”