In 2014, the insurgency escalated dramatically following the conquest of Mosul and major areas in northern Iraq by the Islamic State in Iraq and Syria (ISIS), a Salafi jihadist militant group and unrecognised proto-state that follows a fundamentalist, Wahhabi doctrine of Sunni Islam. ISIL gained global prominence in early 2014 when it drove Iraqi government forces out of key cities in its Western Iraq offensive, followed by its capture of Mosul and the Sinjar massacre, thereby merging the new conflict with the Syrian Civil War, into a new, far deadlier conflict.