(CNN)“You will conquer Rome and own the world,” ISIS leader Abu Bakr al-Baghdadi told his followers in July 2014.
In the previous month, a few hundred ISIS fighters had seized Mosul, Iraq’s second-largest city, in a matter of hours. They drove thousands of Iraqi troops from the city, in the process getting their hands on a huge arsenal of US-supplied weaponry Iraqi forces had left behind. They went on to conquer a string of towns and cities, reaching the outskirts of Baghdad.
At its height, Baghdadi’s so-called caliphate reigned over a realm the size of Britain, with 10 million people under its sway. Its sudden catapult to world attention, combined with an uncanny mastery at social media and slick video production, attracted thousands of people from around the globe eager to take part in the new utopian experiment.