With AQI and its Syrian affiliate/rival Al Nusra increasingly in the news, here is a brief rundown of AQI’s history.

Al Qaeda in Iraq got its start in 2003, originally called Jama’at al Tawhid wal Jihad (The Group for Monotheism and Jihad). It was founded by Abu Musab al Zarqawi, a would-be mujahid who got to Afghanistan after the Soviets departed. Unable to take part in the jihad against the Soviets, he turned his attention to overthrowing the Kingdom of Jordan, where he was imprisoned until being released in 1999. He then traveled to Afghanistan and trained with other Islamists near Herat, until traveling to northern Iraq to join forces with Ansar al Islam.

Michael Ledeen, in his book The Iranian Time Bomb, linked Zarqawi to both Al Qaeda and Iran as early as 2002. While Zarqawi’s activities in Iraq have gained considerable attention, there are multiple court cases pointing to his activities and agents in Germany and Italy as well. The fact that Ansar al Islam, an affiliate of Al Qaeda, fled to Iran in the aftermath of the 2003 US invasion also tends to support the contention that the Mullahs have supported Al Qaeda, at least against the West.

In October 2004, Zarqawi openly pledged allegiance to Osama Bin Laden and the core of Al Qaeda, changing the name to Al Qaeda in Iraq. A month later, US Marines stormed Fallujah in order to root out the elements of AQI that had dug into the city. The majority of the leadership managed to escape the assault.

AQI’s tactics focused less on guerrilla attacks, involving small arms and indirect fire on US and Iraqi forces, and more toward high-profile suicide bombings. While they did still target US forces, they were increasingly targeting Shia Iraqis, a trend that was going to raise concerns with the core Al Qaeda leadership.

In July 2005, Zarqawi sent a letter to Ayman al Zawahiri, outlining his strategy for Iraq. While he does stress driving the US and Coalition forces out of the country and establishing Shariah rule, the majority of the letter is a lengthy screed against the Shia and those Sunnis who would not sacrifice themselves alongside Zarqawi’s hardliners. (He refers to the shaykhs as “Sufis”—who are considered heretics by both Sunni and Shia—as a way of disparaging them for not embracing bloody jihad as he has.) He emphasized striking the Shia as a way to “drag the Muslim nation into the battle.”

AQI continued to claim responsibility for multiple high-profile bombings and kidnappings in the months that followed. They were also suspected in the rash of crude chlorine bombs that were detonated in 2006-2007. Increasingly, their activities were aimed at killing as many Shia as possible. Shortly after Zarqawi’s letter, a response, penned by Ayman al Zawahiri, called on him to stop targeting Shia sites so much, citing a need to unify the Muslim Ummah against the infidels. Zarqawi ignored the correspondence, leading to a breakdown in relations between the core Al Qaeda and its Iraqi affiliate, at least until Zarqawi’s death in an airstrike in June of 2006.

In January of the same year, Zarqawi set up the Mujahideen Shura council as an umbrella organization for the Sunni jihadists operating in Iraq. Zarqawi’s network had already become something of a hub for would-be mujahideen coming into the country; he had one of the largest networks of contacts. AQI proceeded to lump all of their operations under the title of the MSC, until October, when Abu Ayyub al Masri declared the Islamic State of Iraq. This became the new umbrella organization and AQI claimed any further attacks under the auspices of ISI.