ISIS traces its roots to one of the radical groups that emerged in Iraq during the violent years that followed the 2003 American invasion. The group merged with other extremist groups in Syria to form what is now known as ISIS. Its goal from the beginning has been to re-establish a state ruled by strict Islamic law, known as a caliphate, like the ones that dominated the Middle East in past centuries. It also aims to destroy the West.
The group’s followers, Sunni Muslims, are engaged in a bitter rivalry with members of Islam’s other major sect, the Shiites. (That’s why ISIS sees the Shiite-led governments of Iraq and Syria as enemies.)
When Syria erupted into a civil war in 2011, ISIS took advantage of the disorder and began seizing territory. In December 2013, the group turned its attention back to Iraq, capturing a vast area of land and terrorizing people under its control. It publicly executed opponents, sold thousands into slavery, and forced religious minorities to convert to Islam or die. It also seized oil refineries, required people to pay high taxes, and stole hundreds of millions of dollars from Iraq’s national bank. In June 2014, ISIS declared its conquered territory the new caliphate of the Islamic State.
In response, then-President Barack Obama authorized a bombing campaign intended to wipe out ISIS. Since then, an international coalition led by the U.S. has conducted more than 12,000 airstrikes against ISIS in Iraq and 10,000 in Syria.