Ukraine and Russia have agreed to implement a "full and comprehensive" ceasefire in eastern Ukraine by the end of 2019, after top-level talks.
Russian President Vladimir Putin and his Ukrainian counterpart Volodymyr Zelensky met face to face in Paris on Monday.
Five-and-a-half years of fighting between government forces and Russian-backed rebels have cost 13,000 lives.
The negotiations were brokered by the leaders of France and Germany.
They follow a big prisoner swap and the withdrawal of Ukraine's military from three key areas on the front line.
French President Emmanuel Macron and German Chancellor Angela Merkel co-hosted the talks at the Élysée Palace.
Mr Zelensky's recent military and diplomatic moves are aimed at securing peace, but there have already been angry reactions among his opponents, who have warned against conceding too much to Russia.
So how did we get here?
Mr Zelensky, a former comic actor, was elected president of Ukraine in a landslide victory in April following a campaign built around bringing peace to eastern Ukraine.
Since then, his strategy has focused on trying to restart talks with Moscow. For that to happen Mr Zelensky has had to agree to some Russian conditions, including pulling back Ukrainian troops in the eastern towns of Stanytsia Luhansk, Petrivske, and Zolote.
In June, Ukrainian troops and pro-Russian separatists withdrew a kilometre from Stanytsia Luhanska. By late October, the Ukrainians and separatists had disengaged from Zolote and early in November they pulled back from Petrivske.
Nato and Western intelligence experts have repeatedly accused Russia of sending heavy weapons and combat troops into eastern Ukraine to help the rebels.
Russia denies that, but admits that Russian "volunteers" are helping the rebels.
In September, Mr Zelensky won praise for a long-awaited prisoner swap with Russia – he described it as a "victory" that had emerged from personal phone contact with the Russian president.
To pave the way for the summit, President Zelensky accepted a 2016 deal granting special status to the separatist-held parts of Ukraine's Donbas region.
The "Steinmeier formula" aims to break the impasse over peace agreements reached at the height of the fighting. It details free and fair elections in the east under Ukrainian law, verification by the Organisation for Security and Co-operation in Europe (OSCE), and then self-governing status in return.
What triggered the deadly conflict?
Pro-Russian separatists seized control of large swathes of Donetsk and Luhansk regions in April 2014, just after Russia's annexation of Ukraine's Crimea peninsula.
It was an insurgency against the new pro-Western authorities in the capital Kyiv, who had ousted the pro-Russian President, Viktor Yanukovych, in street protests dubbed the "Maidan Revolution".
The separatists later declared independence from Ukraine – but no country has recognised their "republics".
- March, 2014: Russian forces annex Crimea after President Yanukovych is ousted in Kyiv,Read More – Source