It had appeared to be a conflict frozen in time, but the operation launched with blistering speed by Syrian opposition fighters has turned all of that upside down.
It is also a potent reminder of the complexity of the Syrian conflict.
What was a stalemate has revealed that the regime of President Bashar al Assad may very well be standing on clay feet.
Whether the rebel push continues its momentum and transforms into a wider offensive remains to be seen – but its significance politically and militarily is immense.
Aleppo was once the country’s largest city and was a key battleground in the civil war – it has also been a stronghold for the regime.
Image: Rebels stand in front of University of Aleppo. Pic: Reuters
What’s happening now is a major blow to the government as it shows how fragile its grip on power has become.
It also demonstrates that the rebels have the determination and the military capability to challenge regime authority in key strategic areas.
The rebels comprise many different groups who’ve fought against the regime since the start of the Syrian uprising.
Among them, the biggest is Hayat Tahrir al Sham, which controls most of the north-western territory held by the opposition.
Image: Opposition forces take control of areas outside Aleppo. Pic: AP
The group was linked to the terrorist group al Qaeda but has renounced those ties.
Much of the video that’s emerging is reminiscent of the violent uprising against the Assad dictatorship in 2011 – descending into a bloodbath from the so-called ‘Arab Spring’.
Officially, the offensive was launched as a way of stopping regime air strikes on opposition-held territory.
It may be that the rebels themselves are surprised by the lack of government resistance and how successful they’ve been in the space of three short days.
The Syrian government has portrayed what’s happening as a “large-scale terrorist attack” and has vowed to reverse the losses.
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There are of course wider questions as to why this is happening now?
President Assad would most likely have lost the war had he not been bailed out by the Russian air force and the Iranian Revolutionary Guard, as well as a tapestry of militant groups – including Hezbollah.
Russia is struggling for resource in Ukraine and has diverted its air force from the Syrian theatre.
Iran and its proxies have been battered by Israel after they tried to exploit the carnage of the 7 October Hamas attack on Israel.
With these forces not as strong as they were, there’s been a chink in the regime’s armour and the rebels it would seem have seen their chance and not let the opportunity escape.
The question now is whether the opposition fighters will be able to remain on the front foot and consolidate their position and perhaps even launch further attacks on centres of power.
At the moment, the situation remains highly volatile and uncertain.
The advance certainly challenges the established order, but it is still far from clear whether this is a setback for the regime, or the start of a major phase of escalation.
Donald Trump has criticised Vladimir Putin and suggested a shift in his stance towards the Russian president after a meeting with Volodymyr Zelenskyy before the Pope’s funeral.
The Ukrainian president said the one-on-one talks could prove to be “historic” after pictures showed him sitting opposite Mr Trump, around two feet apart, in the large marble hall inside St Peter’s Basilica.
The US president said he doubted his Russian counterpart’s willingness to end the war after leaving Rome after the funeral of Pope Francis at the Vatican.
In a post on his Truth Social platform, he said “there was no reason” for the Russian president “to be shooting missiles into civilian areas, cities and towns, over the last few days”.
Image: The two leaders held talks before attending the Pope’s funeral
He added: “It makes me think that maybe he doesn’t want to stop the war, he’s just tapping me along, and has to be dealt with differently, through ‘Banking’ or ‘Secondary Sanctions?’ Too many people are dying!!!”
The meeting between the US and Ukrainian leaders was their first face-to-face encounter since a very public row in the Oval Office in February.
Mr Zelenskyy said he had a good meeting with Mr Trump in which they talked about the defence of the Ukrainian people, a full and unconditional ceasefire, and a durable and lasting peace that would prevent the war restarting.
Other images released by the Ukrainian president’s office show Sir Keir Starmer and French President Emmanuel Macron were present for part of the talks, which were described as “positive” by the French presidency.
Mr Zelenskyy‘s spokesman said the meeting lasted for around 15 minutes and he and Mr Trump had agreed to hold further discussions later on Saturday.
Image: The world leaders shared a moment before the service
Image: Donald Trump and Volodymyr Zelenskyy meet in the Basilica
But the US president left Rome for Washington on Air Force One soon after the funeral without any other talks having taken place.
The Ukrainian president’s office said there was no second meeting in Rome because of the tight schedule of both leaders, although he had separate discussions with Mr Starmer and Mr Macron.
The French president said in a post on X “Ukraine is ready for an unconditional ceasefire” and that a so-called coalition of the willing, led by the UK and France, would continue working to achieve a lasting peace.
There was applause from some of the other world leaders in attendance at the Vatican when Mr Zelenskyy walked out of St Peter’s Basilica after stopping in front of the pontiff’s coffin to pay his respects.
Image: Donald Trump and the Ukrainian president met for the first time since their Oval Office row. Pic: Reuters
Sir Tony Brenton, the former British ambassador to Russia, said the event presents diplomatic opportunities, including the “biggest possible meeting” between Mr Trump and the Ukrainian leader.
He told Sky News it could mark “an important step” in starting the peace process between Russia and Ukraine.
Professor Father Francesco Giordano told Sky News the meeting is being called “Pope Francis’s miracle” by members of the clergy, adding: “There’s so many things that happened today – it was just overwhelming.”
The bilateral meeting comes after Mr Trump’s peace negotiator Steve Witkoff held talks with Mr Putin at the Kremlin.
They discussed “the possibility of resuming direct negotiations between Russia and Ukraine”, Kremlin aide Yuri Ushakov said.
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On an extraordinary day, remarkable pictures on the margins that capture what may be a turning point for the world.
In a corner of St Peter’s Basilica before the funeral of Pope Francis, the leaders of America and Ukraine sit facing each other in two solitary chairs.
They look like confessor and sinner except we cannot tell which one is which.
In another, the Ukrainian president seems to be remonstrating with the US president. This is their first encounter since their infamous bust-up in the Oval Office.
Image: The two leaders held talks before attending the Pope’s funeral
Other pictures show the moment their French and British counterparts introduced the two men. There is a palpable sense of nervousness in the way the leaders engage.
We do not know what the two presidents said in their brief meeting.
But in the mind of the Ukrainian leader will be the knowledge President Trump has this week said America will reward Russia for its unprovoked brutal invasion of his country, under any peace deal.
Mr Trump has presented Ukraine and Russia with a proposal and ultimatum so one-sided it could have been written in the Kremlin.
Kyiv must surrender the land Russia has taken by force, Crimea forever, the rest at least for now. And it must submit to an act of extortion, a proposed deal that would hand over half its mineral wealth effectively to America.
Image: The world leaders shared a moment before the service
Afterwards, Zelenskyy said it had been a good meeting that could turn out to be historic “if we reach results together”.
They had talked, he said, about the defence of Ukraine, a full and unconditional ceasefire and a durable and lasting peace that will prevent a war restarting.
The Trump peace proposal includes only unspecified security guarantees for Ukraine from countries that do not include the US. It rules out any membership of Ukraine.
Ukraine’s allies are watching closely to see if Mr Trump will apply any pressure on Vladimir Putin, let alone punish him for recent bloody attacks on Ukraine.
Or will he simply walk away if the proposal fails, blaming Ukrainian intransigence, however outrageously, before moving onto a rapprochement with Moscow.
If he does, America’s role as guarantor of international security will be seen effectively as over.
This could be the week we see the world order as we have known it since the end of the Second World War buried, as well as a pope.