On June 29 2014 – nearly three years ago to the day – Abu Bakr al-Baghdadi took the pulpit at the Great Mosque of Al-Nuri in Mosul in northern Iraq. He announced the creation of a new Islamic State that stretched across the borders of Iraq and Syria. Declaring himself Caliph Ibrahim, the leader of all Muslims, he implored the faithful from across the world to make the pilgrimage to come and serve. Yesterday, in the midst of what are likely to be the final stages in the Battle for Mosul, the Islamic State appears to have destroyed the Great Mosque of Al-Nuri and its iconic leaning minaret. As the Iraqi poet Ahmed Zaidan has said, the Great Mosque was not only a significant cultural heritage site for Muslims in general, but it was also regarded as an essential part of the Mosul skyline - a symbol of the city’s long past and diverse communities. The building itself was erected in 1172 by the great Nur Al-Din ibn Zengi (1118-1174), widely regarded as the man who launched the first successful holy war against Western crusaders. Although there are conflicting reports about who destroyed the mosque – the IS blames American airstrikes – the available footage online suggests the site was bombed with explosives from the inside. Such destruction certainly fits with their pattern of the Islamic State’s aggressive destruction of religious imagery, as we have described recently. It would be cynical and unwise to dismiss the destruction of the Great Mosque as a last desperate effort by the IS, a fit of rage in the face of imminent defeat. From their inception, the IS have been engaged as much in a symbolic war as they have a military one. And as their capacity to hold and defend territory shrinks, this war becomes key to expressing their power and ideology and imploring their adherents to continue the fight.