In the late ‘90s, there was a group of very dangerous Islamic radicals in Jordan. They were such a threat that the country had reopened an abandoned prison in the middle of the desert as a way to isolate them from spreading ideas to other prisoners.
There is a tradition in Jordan of a nationwide amnesty of prisoners with every new king, and King Abdullah II followed suit in 1999. The amnesty released many of those radicals, including Abu Musab al-Zarqawi, a hardened street thug with impeccable leadership qualities and aspirations of an ultra-conservative caliphate in the Middle East.
Zarqawi rose in power and established the Islamic State of Iraq and Syria. A few actions from the United States spurred the growth of ISIS, even as leadership changed following Zarqawi’s death.