Vienna - Since the start of Syria's war in 2011, numerous efforts to halt the conflict through diplomacy have failed.
With a new round of UN-led negotiations under way in Vienna, here is a look back at other attempts at talks.
'End of Arab solutions'
In January 2012, two months after an initial bid to end the violence, leading Arab diplomats adopt a plan that would transfer power from President Bashar al-Assad to a coalition cabinet.
But the Damascus government rejects the proposal, declaring "an end of Arab solutions", and vows to crush the rebels.
Geneva I, ambiguous
In June 2012 global powers meeting in Geneva draw up a plan that would install a transition government but does not spell out what would happen to Assad.
Among those involved are the five permanent members of the UN Security Council - Britain, China, France, Russia and the United States - plus the Arab League, Turkey and the European Union.
They differ over what the plan really means, however, with the United States saying it paves the way to a "post-Assad" period.
China and Russia, allies of Assad, insist it is up to Syrians to decide their future.
Geneva II, no agreement
In January 2014 the first talks between Syrian opposition groups and the government are held in Geneva under the auspices of Russia and the United States.
On February 15, after a second fruitless session, UN mediator Lakhdar Brahimi calls an end to the talks and resigns.
Vienna plan
In September 2015 Russia lends its military backing to Assad's forces, which have been struggling against Gulf- and Western-backed rebels. It is a game-changer for the regime.
In November 2015 the International Syria Support Group (ISSG) is set up in Vienna, grouping 23 world or regional powers and multilateral organisations.
They include Russia, Saudi Arabia, Turkey, the United States, the United Nations, the European Union and, for the first time, Iran.
The group draws up a transition outline but the question of Assad's future is still not resolved.
In December the UN Security Council unanimously endorses the Vienna peace process.
Nine rounds at UN
In early 2016 three rounds of UN-supervised indirect negotiations are held in Geneva between regime and opposition groups. The parties do not talk face to face.
The negotiations stall over arrangements for a transition and run up against violations of a ceasefire.
In March, May and July 2017 there are four more rounds of indirect talks without result.
An eighth round of talks in Geneva in December fails to get the different parties even to talk to each other. It was a "golden opportunity missed", UN envoy Staffan de Mistura says afterwards, blaming in particular the government delegation's apparent lack of interest.
On January 25, a ninth round is held in Vienna, having been relocated from Geneva for logistical reasons.
US sidelined
In late 2016 regime-backers Russia and Iran and rebel-backer Turkey take over the peace process, sidelining the United States.
In January 2017 the three sponsors organise talks in Astana, Kazakhstan, between representatives of the regime and a rebel delegation.
They hold seven rounds of negotiations, reaching an accord on the setting up of four "de-escalation" zones in Syria, leading to a decrease in violence.
A peace congress is scheduled in Russia's Black Sea resort of Sochi on January 30.
