Who is Tahrir al-Sham, the rebel group that seized control of Aleppo?

On Wednesday, rebels launched their largest offensive against the Syrian government in years.

By Saturday, they had control ‘Most’ of Aleppo, the country’s second city.

The raid prompted Russia’s first attack on Aleppo since 2016 and the withdrawal of Syrian troops from the city.

The attack was led by the Islamist militant group Hayat Tahrir al-Sham (HTS), which has a long and complicated history in the Syrian conflict.

HTS was founded under a different name; victorious frontIn 2011, it became a direct affiliate of Al Qaeda.

Islamic State leader, Abu Bakr al-Baghdadialso participated in its formation.

It is considered one of the most effective and lethal groups targeting President Assad.

But its jihadi ideology appeared to be its driving force rather than revolutionary fervor, and it was seen at the time as being at odds with the main rebel alliance under the Free Syria banner.

But in 2016, the group’s leader, Abu Mohammed al-Jawlani, publicly broke with Al Qaeda. Disband Al-Nusra Front and form new organizationA year later, the group merged with several other similar groups and changed its name to Hayat Tahrir al-Sham.

For the past four years, it has felt as though the war in Syria was actually over.

President Bashar Assad’s rule has been largely uncontroversial in the country’s major cities, while some other parts of Syria remain outside his direct control.

These include Kurdish-majority areas in the east, which have been more or less outside the control of the Syrian state since the early days of the conflict.

The revolution against Assad’s rule began in the south in 2011, and although it was relatively peaceful, some unrest persisted.

Across the vast Syrian desert, die-hard elements of the group calling itself the Islamic State still pose a security threat, especially during truffle hunting season when people travel to the region in search of the lucrative delicacy.

In the northwest, Idlib province is controlled by jihadist and rebel groups driven there at the height of the war.

The leading force in Idlib is HTS, which launched a surprise attack on Aleppo.

For years, Idlib has been a battleground that Syrian government forces have tried to regain control of.

but 2020 ceasefire brokered by RussiaTürkiye, which has long been Assad’s main ally and backs the rebels, has largely held its ground.

About four million people live there, most of them displaced from towns that Assad’s forces recaptured from rebels in a brutal war of attrition.

Aleppo was one of the bloodiest battlefields and one of the rebels’ biggest defeats.

To achieve victory, Assad relied on Russian airpower and Iranian military help on the ground—mainly through Iranian-backed militias.

That includes Hezbollah.

There is no doubt that Hezbollah’s recent setbacks Israel’s attack on Lebanonand Israeli attacks on Iranian military commanders in Syria played an important role in the decision by jihadists and rebel groups in Idlib to take sudden and unexpected action against Aleppo.

Over time, HTS has established a power base in Idlib, becoming the de facto local government, although its legitimacy efforts have been undermined by alleged human rights abuses.

It has also been involved in some bitter infighting with other groups.

Its ambitions outside Idlib have become unclear.

Since the break with Al Qaeda, its goals have been limited to trying to establish fundamentalist Islamic rule in Syria, rather than establishing a broader caliphate as the Islamic State has tried and failed to do.

So far, it has shown few signs of trying to reignite Syria’s conflict on a large scale and re-challenge Assad’s rule over much of the country.

Additional reporting by Maia Davies.