"The groundwork for ISIS was arguably laid long before the invasion, and if there was one person responsible for the group’s modus operandi, it was Abdulrahman al-Qaduli, an Iraqi from Nineveh better known by his nom de guerre, Abu Ali al-Anbari—not Zarqawi. It was Anbari, Zarqawi’s No. 2 in his al-Qaeda years, who defined the Islamic State’s radical approach more than any other person; his influence was more systematic, longer lasting, and deeper than that of Zarqawi."This is based on material circulated on social media in Al-Naba, after Anbari was killed. Anbari himself was influenced by audio sermons coming out of Afghanistan and Chechnya in the 1990s.