With the capture of Mosul, the Islamic State of Iraq and al-Shams, or ISIS, gained American weapons and 500 billion Iraqi dinars, which at $429 million, reportedly makes the organization the most well-funded terrorist network in the world. Gold bullion reserves were also raided, adding an as yet uncalculated amount of wealth to the group’s funding, which now exceeds the operating budget of even al Qaeda. Additionally, ISIS freed about 1,000 inmates from Mosul’s central prison, and many joined its militia.

It is, however, more than money, men, and equipment that sets ISIS apart as a unique player in the Middle East. Unlike al Qaeda or other affiliated groups operating in Syria, ISIS, as its name suggests, is not just one of many jihadist groups furthering radical Sunni Islamic causes. It seeks to create an actual Sunni nation state. With cash reserves on par with that of small countries, and an apparently organized and motivated structure, it seems right now that it may do just that.

ISIS is now setting out to not just occupy Nineveh, which Mosul was the provincial capital of, but to govern it. Sharia law has reportedly been instituted in the pursuit of a renewed Islamic Caliphate. However, the Sunni force sees no room for Shia Muslims in their future kingdom and has apparently declared that it will destroy Shia shrines and cemeteries.

For Sunni Muslims, the Caliphate is the Islamic state ruled by the true successor of Mohammad, the Caliph. Thus the construction of a Caliphate by definition exacerbates the conflict between not just radical Islamists and secularists, but also between Sunni and Shia. Sunni and Shia are divided over which are the spiritual heirs to Mohammad. Shia cannot embrace a Sunni Caliphate not merely for that reason, but also because of remembered oppression under the Sunni Caliphate.

There is speculation that the ease with which ISIS pacified Nineveh stems not just from the Sunni population there, but also from sympathetic military officers who ordered the American trained government forces to stand down. The region is predominately Sunni and, while many residents have fled, they are reportedly more fearful of a government counterattack than of ISIS rule.

It seems clear, then, that while Iraqi and Kurdish forces may be able to hold off further advances by ISIS in the coming days, the counterinsurgency will be brutal. Well-funded, well-equipped, surrounded by fellow Sunni Muslims in pursuit of a Sunni Caliphate, ISIS and the de facto state of Nineveh it has already created may become a more permanent part of the Middle Eastern landscape.