NEW YORK –

The city of Hatra in Iraq, a once-wealthy metropolis that withstood sieges by Roman emperors, was finally conquered this month — by the Islamic State group. To celebrate, the jihadists released an elaborate video. It begins with an aerial shot of the historic site (Hatra fell to ruin in the third century), with an overlay of graphics highlighting some of its buildings in red and labeling them "idols and statues." The video then shows fighters attacking the site's ancient sculptures with sledgehammers, pickaxes and even, for those works out of reach, sprays of bullets from an AK-47. The black flag of the Islamic State is superimposed over the corner of most frames, terrorism's malevolent trademark

The terrorist group has posted other videos and flooded its social media outlets with images of its destruction of parts of the ancient site of Nimrud and of sculpture in the Mosul Museum. (Its troops have been fighting for control of Palmyra in Syria as well.) Video voice-overs explain that "Muhammad commanded us to shatter and destroy statues" in order to root out shirk, or idolatry. "It is easy for us to obey" Muhammad's orders, one video boasts, "even if this costs billions of dollars." Most reporting in the Western press on this wave of destruction has taken the Islamic State at its own word. But this is a mistake. Far from simply wanting to destroy "idolatrous," pre-Islamic art, the groups' actions are motivated by complex and systematic goals.

One aim is profit — despite their spokesman's claims about ignoring the "billions of dollars" such antiquities could be worth. The videos show the destruction only of large, unwieldy and easily identifiable works. These antiquities would be difficult to transport out of Syria and Iraq and would not find willing buyers, since they could be recognized and seized as stolen property.