A FEW details looked out of place: the watch on the speaker’s right wrist, a fan whirring behind him and machine guns propped against the walls. Otherwise, as a thickly bearded, black-robed preacher slowly mounted the pulpit of the Mosque of Noureddin Zangi in the Iraqi city of Mosul on July 4th, the first Friday of Ramadan, the scene could have been set 750 years ago. Just as then, when the mosque’s builder and namesake ruled the surrounding region and rallied the faithful against Christian Crusaders in Palestine, the sermon was a rousing call for Muslims to fall in and join the jihad.

The difference is that this preacher, Abu Bakr al-Baghdadi, styles himself not a local emir but a caliph, the presumed commander of all the world’s 1.5 billion faithful. And another difference: his jihad has so far been waged not so much against infidels as against fellow Muslims. But perhaps the most significant innovation is that Mr Baghdadi had his performance filmed in high-resolution video, a slick advertisement both for his band of international terrorists, now titled the State of the Islamic Caliphate (SIC), and for his hitherto-reclusive self.

Mr Baghdadi’s rise appears meteoric. When he took its helm four years ago his group, which started as a stepchild of al-Qaeda in the armed resistance to America’s invasion of Iraq in 2003, had been all but smashed. Its roaring comeback started with a wave of bombings targeting Iraqi Shias. In 2012 it expanded into Syria, attracting thousands of jihadists from around the world to become the strongest rebel militia and establishing a proto-state centred on the city of Raqqa. Unlike earlier jihadist groups, SIC has created a full-scale administrative apparatus, including institutions such as courts and social-welfare programmes.

Last month it returned to Iraq, leading a charge by Sunni insurgents towards the capital, Baghdad. Since Mr Baghdadi’s declaration of a caliphate on June 30th SIC has captured more land in Iraq, secured a new chunk of Syria around the eastern city of Deir ez-Zor, and now threatens to push north and west into areas held by rival Syrian rebel groups.

A mix of ruthlessness, astute publicity and clever tactics has allowed SIC to punch above its strength, estimated anywhere between 7,000-20,000 fighters. Its expansion in both Iraq and Syria has followed a pattern. Potential allies such as tribal groups and local militias are wooed with cash, guns and promises. Leaders who resist pledging allegiance, as well as allies who have served their purpose, are then targeted for assassination. Recent victims reportedly include the incumbent imam of the Noureddin Zangi mosque and a dozen other Sunni clerics in Mosul, as well as former Iraqi army officers who helped plan SIC’s stunning seizure of Iraq’s second-largest city last month.

Yet Mr Baghdadi faces some big obstacles. Aside from young Islamist hotheads, like-minded jihadist groups and co-opted local militias, few Muslims anywhere have responded to his claims with enthusiasm. The International Union of Muslim Scholars, a group of Sunni clerics chaired by Yusuf al-Qaradawi, an influential Egyptian preacher, lambasted SIC’s declaration of a caliphate as illegitimate, destructive not only to the Sunni uprisings in Iraq and Syria but to Islam in general. Not even Abu Muhammad al-Maqdisi, a Jordanian cleric released from prison last month and widely respected in jihadist circles, endorses the caliphate project. “Reform yourselves, repent, stop killing fellow Muslims and distorting religion,” he commanded in a recent statement.

Perhaps most tellingly, a survey carried out in Syria in May by ORB, a British firm that specialises in opinion-taking in war zones, found that only 4% of respondents believed that SIC “best represents the interests and aspirations of the Syrian people”. Even in their stronghold of Raqqa, the group’s popularity was an unimpressive 24%. No wonder Mr Baghdadi dismisses democracy as an infidel abomination.