The Syrian opposition has lost a strategic town that came to symbolise its daring but uneven struggle against President Bashar Al Assad and the failure of Turkey to help those whose cause it espoused.
Under the cover of Russian bombing overnight on Monday, loyalist forces entered the town of Khan Sheikhoun, the target of a sarin gas attack on April 4, 2017, which killed 89 people. The UN blamed the regime for the attack.
Khan Sheikhoun, in rural Idlib province, was a centre of non-violent resistance against Mr Al Assad’s rule before the Syrian uprising turned into a large-scale armed rebellion in 2012.
Militants later dominated the rebel scene, partly due to the regime releasing top Al Qaeda-linked operatives from its jails in 2011 in a move that significantly undermined the civic revolt.
That helped Mr Al Assad to appeal to his minority Alawite base as the only option to prevent a militant takeover.
On Monday, Al Qaeda-linked Hayat Tahrir Al Sham announced that it had withdrawn to the outskirts of Khan Sheikhoun because of heavy bombardment.
The capture of the town is part of an offensive to encircle remaining opposition forces in the nearby Hama governorate,
These forces include Jaish Al Ezza, a rebel brigade that had resisted takeovers by Al Qaeda and its ideology.
The group is one of the last remaining units of the Free Syrian Army, a loose rebel alliance formed by officers who defected from the army and led the armed revolt before the militant invasion.
Now the fate of Jaish Al Ezza and civilians in the areas in which it is present is set to resemble cities and towns that fell to the regime after Russian bombardment and sieges resulted in surrenders brokered by Moscow, forcibly transferring inhabitants to areas of Idlib near the Turkish border.
On Sunday, an armoured column sent by Ankara towards a Turkish observation point south of Khan Sheikhoun was stopped by air strikes that appeared to have been a Russian warning.
Early in the uprising, Turkish President Recep Tayyip Erdogan supported the revolution, saying Turkey would not allow the regime to repeat the massacres of thousands of civilians that followed an uprising against Assad family rule in the 1980s.
Downtrodden rural Syrians identified with Mr Erdogan, as Ankara backed rebel attacks that were ultimately defeated by the Russian intervention in late 2015.
Turkey has since reached understandings with Moscow that helped Ankara to take over areas in northern Syria.
These areas had fallen under the control of a Kurdish militia linked to the banned Kurdistan Workers’ Party.
Ankara had played a major role in preventing rebel groups it has supported from joining a US effort to defeat ISIS, forcing Washington to rely on the Kurdish militia, which is not interested in Assad's downfall.
But Turkey, to the anger of Russia, entered talks with the US last week to create a buffer zone in northern Syria that Ankara said would be free of the Kurdish militia.
Those talks may have contributed to a breakdown in understandings between Moscow and Ankara over Idlib and an intensification in recent weeks of the Russian air campaign.
Moscow says it is attacking terrorists but the bombings have killed hundreds of civilians in Idlib and driven hundreds of thousands to flee to areas nearer to the Turkish border under Ankara’s influence.
Russian and regime strikes on schools, hospitals and other civilian buildings in Idlib prompted UN Secretary General António Guterres to start an investigation this month, bringing a brief halt to the bombing.
The bombing appears aimed at opening the M5, the main highway from Damascus to Aleppo, and the M4, a main link between Aleppo and the city of Latakia on the Mediterranean coast, where Russian forces are concentrated.
Rebels still present in the territory could prevent the regime from securing the highways. But to withstand the onslaught, they would need Turkish support that, as Khan Sheikhoun shows, has been fickle.
Ankara does not want to be drawn into a direct confrontation with Russia but it also has used its Syrian allies to serve its own interests.