Aleppo's other battle line

One shell demolished the front of the house, leaving a gaping hole where the arched gateway once stood. A second gouged out a crater 10ft wide in the walled garden and a third smashed into bedrooms and the library. The family of seven living there all suffered injuries, three of them severe and needing emergency surgery.

"We thank Allah that they are alright. But this home has now gone. It is 390 years old," said Awni Abu Riadh. "There was a fountain in the garden which was one of the oldest working ones in the city. My uncle Ahmed had collected a history of this house, but that has gone with the library. Look all around. Bashar's army are ruining this great city; they are trying to take away our past."

Compared with its surroundings, the beautiful Ottoman house of Ahmed Mansour – now destroyed – is relatively new. Standing on the rubble, one can see, through other buildings damaged by the fighting, the Citadel of Aleppo, built on original fortifications which date back to 3000 BC; a World Heritage Site of history and culture which had been restored to some of its glory through extensive excavation and conservation.

The Assyrians and Babylonians used a fortress in this place, with its command of the plains beyond. Alexander the Great captured it on his way to Persia; one of his generals enlarging the settlement which later became Aleppo. Byzantine and Sassanian emperors fought endless battles over the city and citadel for its strategic position and rich hinterland. Saladin, the great general, planned many of his campaigns against the Crusaders from here; Baldwin II, one of the Christian kings of Jerusalem, was imprisoned in the castle. Aleppo was subsequently put to the sword by Genghis Khan's Mongols and the Tartars of Tamerlaine.

The citadel is now once more a battleground. The forces of the regime occupy the castle and the rebels the Iron Gate, Bab al-Hadeed. The cobbled streets, shaded courtyards and covered bazaar – one of the most famous in the region – are used to trade fire. Increasingly, there is damage from air strikes, one of them blowing up a 17th century bathhouse and surrounding properties.

This, the second frontline of Aleppo, is a vast contrast to the first, Salaheddine, which has been pulverised by bombing and air strikes and is now a dark and forbidding place of constantly echoing gunfire and the stench of bodies buried beneath collapsed houses.

At the Aleppo Citadel, the destruction is not on that scale. There is more life than death; flocks of turtle doves rise at the sound of battle but return to their nests, and enough architecture remains standing to draw admiration from the rebel fighters. "That mosque, that mosque is beautiful, isn't it?" said Mohammed Khaladi of the Abu-Bakr brigade, from the nearby town of Al-Bab. "It is very old. It is especially used for special occasions. Famous sermons have come from there," Not this day however; caught in the crossfire, its walls already pockmarked by bullets, the doors of the house of worship remained shut.

The main problem came from regime snipers using the arrowslits on the castle's walls to fire down, with some success. "They are a big problem," acknowledged Mohammed Khaladi. "They are very well protected, very difficult to hit. We have the castle surrounded and we have tried to capture it a few times, but it is difficult."

The last attempt, a charge uphill to shouts of "Allah Hu Akhbar", ended at the moat, which could not be crossed. The regime troops inside could offer thanks to Saladin's son, Sultan al-Zahir al-Ghazi, who, during his 18-year rule from 1193, doubled the depth of the moat, strengthened the approach way, and built a bridge and viaduct to better co-ordinate defence.

Jamal Ali Zaied was shot during the operation. "It was a hard climb up the hill. I had just stopped to rest for a second when I felt pain in my arm and it started bleeding heavily," he explained. "I had to climb back down and with only one hand my rifle slipped off. I couldn't get it back because there was so much firing." Like many among the opposition militias, Mr Zaied has had to arm himself, and the loss of the $1,800 (£1,150) Kalashnikov AK-47 was keenly felt, especially as he had not been able to use it effectively. "We have to use RPGs against tanks, not Kalashnikovs. We need heavier weapons to get inside the castle, we need to use more mortars," he said.

Successive conquerors of Aleppo used the artillery of the time – giant catapults flinging boulders to weaken Aleppo's walls, and the Mongols and Tartars made effective use of inflammable "Chinese Fire". Mr Zaied did not know about it, but thought it was a sensible strategy to have taken.

Basel Ahmedi also took part in the rush for the citadel. He had been inside it once, four years ago, for a concert at the old amphitheatre which was used for cultural events before the uprising. "It was classical Arabic music; the setting was very interesting. I would like to see the place again once we get in." Mr Ahmedi had also served in Salaheddine, and being at the castle front was far preferable. "There we had bombing, day night, day night. It is not like that here," he said.

The Old City around the citadel had become a place of refuge for many who had fled Salaheddine; now they find themselves amid fighting and uncertainty once again. Haji Ahmed Mahmoud Makhboul was moving his family for the second time, possibly to a village in the neighbouring Idlib province. "I hope they manage to get peace, we cannot continue to live like this," was his fervent wish. "We had to leave behind everything in Salheddine and we don't know what has happened there. All we now have is what we are carrying."