Vladimir Putin and Hassan Rouhani were hosted by Recep Tayyip Erdogan on Wednesday at the Turkish presidential palace in the capital for what is to be a highly-scrutinized encounter aimed at finding a solution to the brutal civil war entering its eighth year in Syria. 

This high-level meeting followed similar trilateral summits in the Kazakh capital Astana and the Russian Black Sea resort Sochi, both of which produced tentative ceasefire plans that were later implemented with varying success. 

Russia and Iran, who back the Syrian regime of Bashar Al-Assad, and Turkey, who backs Syrian militants opposed to the regime, have demonstrable clout in the civil war. 

Russia's involvement from 2015 reversed the declining powers of Assad, who has since recouped much of his lost territory, including important sites like Aleppo and Eastern Ghouta, one of the last rebel outposts near the capital.

Turkey has invaded northern swathes of Syria, where it has engaged in battles against Kurdish militias it deems as terrorist groups. 

The United Nations' influence in Syria had been repeatedly undermined by Russia, which breached U.N. ceasefire plans repeatedly. 

Notwithstanding, the U.N.'s special envoy to Syria, Staffan de Mistura, commonly attends the Russia-Turkey-Iran talks.