In fighting that has killed at least 300,000 people since March of 2011, in an uprising against President Bashar al-Assad, has taken a huge turn.
The Syrian government and rebel groups have agreed a nationwide ceasefire from midnight (22:00 GMT) on Thursday.
Russia’s President Vladimir Putin announced the deal which was confirmed by Turkey. The two nations back opposing sides and will act as guarantors.
The deal has also been confirmed by the High Negotiations Committee (HNC), regarded by the UN as Syria’s main opposition body. The deal excludes jihadist groups.
If the truce holds, peace talks will be held in Kazakhstan within a few weeks.