The Islamic State (IS), also known as the Islamic State of Iraq and the Levant (ISIL), the Islamic State of Iraq and Syria (ISIS) and by its Arabic acronym Daesh, is a transnational Salafi jihadist group and a former unrecognised quasi-state. Its origins were in the Jai'sh al-Taifa al-Mansurah organization founded by Abu Omar al-Baghdadi in 2004, which fought alongside al-Qaeda during the Iraqi insurgency. The group gained global prominence in 2014, when its militants successfully captured large territories in northwestern Iraq and eastern Syria, taking advantage of the ongoing Syrian civil war. By the end of 2015, it ruled an area with an estimated population of twelve million people, where it enforced its extremist interpretation of Islamic law, managed an annual budget exceeding US$1 billion, and commanded more than 30,000 fighters.

Salafi jihadism, also known as revolutionary Salafism or jihadist Salafism, is a religious-political Sunni Islamist ideology that seeks to establish a global caliphate, characterized by the advocacy of "physical" (military) jihadist attacks on non-Muslim targets. The Salafist interpretation of sacred Islamic texts is "in their most literal, traditional sense", which adherents claim will bring about the return to "true Islam".