Although it is formally Syria's second city, Aleppo has overshadowed Damascus for much of its recent history.
Located close to the Turkish border, it lay at the end of the Silk Road from China, making it a hugely important trading centre for centuries and leaving it with its fabulous architectural legacy of caravanserais and souks.
Its importance was internationally recognised: when the English Levant Company was looking for a Middle East headquarters in the late 16th century, it chose Aleppo.
Mr Assad succeeded in transferring a good deal of commerce to Damascus, but Aleppo still remains Syria's most important industrial city today.
Under Mr Assad's son and successor Bashar, Aleppo remained stable and, even when the uprising against his rule erupted last year, the city proved one of the most reluctant to rebel.
Demonstrators in less subservient towns were frequently heard to chant "Aleppo, where are you?" - a recognition of the opposition's frustration at being unable to turn a city that could spell the difference between Mr Assad's survival and downfall.
Although many of Aleppo's inhabitants remain loyal to the president, the rebels have finally managed to establish a foothold in the city. That they have done so is in part due to the fact that Mr Assad was forced to withdraw troops to protect his capital, leaving Aleppo less well defended.
But even if the president can regain control, Aleppo is much more fractured than it was in the past. To the north, where Islamist currents run strong, the key towns of Azaz, Hreitan and Anadan are now opposition strongholds and the rebels were said to be in control of Azaz yesterday.
But in Aleppo itself, much of the Sunni working class has turned against the regime, something that has manifested itself in a series of arson attacks on factories in the city in recent months.
The factory owners are starting to realise that support for the regime is no longer in their interests. Their employees have turned, trade has been paralysed because it is impossible to move goods to the nearby Turkish border, and the uprising has plunged the country into economic crisis.
The mercantile class that Mr Assad's father wooed so successfully may well be lost to the regime and without Aleppo, the city his family has so long feared, the president's chances of survival look grimmer than ever.
