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 militant organisation and internationally unrecognised quasi-state. IS occupied a significant amount of territory in Iraq and Syria from 2013 to 2016, but lost most of it between 2017 and 2019. In 2014, the group proclaimed itself to be a worldwide caliphate and claimed religious and political authority over all Muslims worldwide, a claim not accepted by the vast majority of Muslims. It is designated as a terrorist organisation by the United Nations and many countries around the world, including Muslim countries. By the end of 2015, its self-declared caliphate ruled an area with a population of about 12 million, where they enforced their extremist interpretation of Islamic law, managed an annual budget exceeding US$1 billion, and commanded more than 30,000 fighters. After a grinding conflict with American, Iraqi, and Kurdish forces, IS lost control of its Middle Eastern territories by 2019, subsequently reverting to insurgency from remote hideouts while continuing its propaganda efforts. These efforts have garnered a significant following in northern and Sahelian Africa, where IS still controls a significant territory. Originating in the Jaish al-Ta'ifa al-Mansurah founded by Abu Omar al-Baghdadi in 2004, the organisation (primarily under the Islamic State of Iraq name) affiliated itself with al-Qaeda in Iraq and fought alongside them during the 2003–2006 phase of the Iraqi insurgency. The group later changed its name to Islamic State of Iraq and Levant for about a year, before declaring itself to be a worldwide caliphate, called simply the Islamic State (الدَّولةُ الإِسْلَامِيَّة, ad-Dawlah al-Islāmiyya). During its rule in Syria and Iraq, the group became notorious for its brutality. It committed genocides against Yazidis and Iraqi Turkmen; engaged in persecution of Christians, Shia Muslims, and Mandaeans; publicised videos of beheadings of soldiers, journalists, and aid workers; and destroyed cultural sites. The group has perpetrated terrorist massacres in territories outside of its control, such as the November 2015 Paris attacks, the 2024 Kerman bombings in Iran, the 2024 Crocus City Hall attack in Russia. Lone wolf attacks inspired by the group have also taken place. After 2015, the Iraqi Armed Forces and the Syrian Democratic Forces pushed back IS and degraded its financial and military infrastructure, assisted by advisors, weapons, training, supplies, and airstrikes by the American-led coalition and Iranian proxy forces, and later by Russian airstrikes, bombings, cruise missile attacks, and scorched-earth tactics across Syria, which focused mostly on razing Syrian opposition strongholds rather than IS bases. By March 2019, IS lost the last of its territories in West Asia, although its affiliates maintain a significant territorial presence in Africa as of 2025.