The Islamic State of Iraq and al-Sham (Greater Syria) [ISIS a.k.a. ISIL (Islamic State of Iraq and the Levant), IS (Islamic State) or DAISH (Al-Dawla al-Islamiya fi al-Iraq wa al-Sham)] has been a product of state failure, civil war and the repression of Sunnis by the Shi’ite government of Nouri al-Maliki in Iraq and by the atrocities of the regime of Bashar al-Assad against its own people in Syria. Almost as much, however, it is the product of the will to power of a branch of a broader Islamist movement that has been active in Iraq for more than a decade, following the American intervention in Iraq in 2003.
Schmid, Alex P. "Challenging the Narrative of the 'Islamic State,'" Research paper for the International Centre for Counter-Terrorism. The Hague, Netherlands: 2015. http://icct.nl/wp-content/uploads/2015/06/ICCT-Schmid-Challenging-the-Narrative-of-the-Islamic-State-June2015.pdf