What happened?
The wave of popular unrest that swept the Arab world came late to Syria, but its once peaceful uprising has evolved into a brutal and increasingly sectarian armed conflict.
Protests demanding greater freedom and an end to corruption began in the southern city of Deraa in March 2011. After security forces opened fire on demonstrators, more took to the streets. By July 2011, hundreds of thousands of people across the country were attending protests demanding President Bashar al-Assad's resignation.
Despite the security forces' concerted and ruthless efforts to crush the "terrorists" and "armed criminal gangs", the uprising continued unabated. Opposition supporters began to take up arms, first to defend themselves and then to oust loyalist forces from their areas.
In February 2012, President Assad pressed ahead with a referendum that approved a new constitution that dropped an article giving the ruling Baath Party unique status as the "leader of the state and society". The opposition denounced it as sham.
Pressure steadily built on Mr Assad as rebels seized control of large parts of the north and east of the country and launched offensives on Damascus and Aleppo, while the opposition National Coalition was recognised around the world as the Syrian people's "legitimate representative".
In 2013, the momentum in the conflict gradually began shifting in Mr Assad's favour, as government forces launched major offensives to recover territory and consolidate their grip on population centres in the south and west. The rebels' appeals for heavy weapons were meanwhile rejected by Western and Gulf allies concerned by the prominence of jihadists affiliated to al-Qaeda.
However, Mr Assad was forced onto the defensive in August 2013 after a chemical weapons attack on the outskirts of Damascus that left hundreds dead. Although the US pulled back from launching punitive military strikes, the president was forced to agree to destroy Syria's chemical weapons.
Where are we now?
Neither side has managed to achieve a breakthrough on the battlefield and the government and National Coalition have reluctantly agreed to a peace conference in Geneva in January 2014.
President Assad is refusing to step aside - a step the National Coalition is insisting on. Meanwhile, the war has produced a humanitarian disaster, leaving more than 100,000 people dead and forcing millions from their homes.
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