After the death of its ultraviolent leader Abu Musab al- Zarqawi in 2006, Al Qaeda in Iraq was led by Abu Ayyub Al-Masri and then by Abu Omar al-Baghdadi.
Th group changed its name to the Islamic State in Iraq (ISI), and began to focus on conquering Iraqi territory as a means of creating a sharia-based state there.
The group concentrated its efforts on gaining territory in the desert region of Anbar province, where discontent with among the Sunni population was rife.
However, their brutal attempts to enforce sharia law turned the local population against them.
Supported by American forces, tribal militias called Sahwat al-Anbar (Anbar Awakening), or alternatively Abna al-Iraq (Sons of Iraq), pushed ISI out of Fallujah and the rest of Anbar in bloody fighting.
Founded in 2005, the Sons of Iraq supported the American troop surge of 2007 and were able to all but defeat ISI. But following victory, they were not integrated into the Iraqi military by the Shiite Prime Minister Nouri al-Maliki, instead being targeted as a potential threat to Shiite majority rule.
As a result they became alienated and many of them have now joined the Islamic State.
The two leaders were killed by a tank shell in 2010 and Abu Bakr al-Baghdadi took over ISI.
He rebuilt some of the popular support that had been lost under the groups two earlier leaders, but also began to develop the organization's strength.
He staged the group’s major comeback by expanding into the Syrian Civil War in 2013.
That’s when he renamed the organization the Islamic State in Iraq and Syria (or the Islamic State in Iraq and Levant – ISIL). But Baghdadi's decision to move into Syria provoked friction with Al-Qaeda's official affiliate in Syria, Jabhat al Nusra. Baghdadi attempted to take over Jabhat al-Nusra, prompting rebuke from Nusra's leader and Al-Qaeda central command.
After multiple failed attempts at mediation by various leading sheikhs in the global jihadist community, the two groups split permanently when the Aymenn al-Zawahiri, leader of Al-Qaeda central angrily expelled ISIS.
Throughout late 2013 and early 2014, ISIS built its power base in Syria. It established a stronghold in Raqqa, ousting all other rebel groups and turning it into a de-facto capital.
Despite a counterattack by other factions sparked by its brutal tactics, ISIS was able to hold its positions and consolidate its power base.
Policies of divide and rule in fractious tribal areas helped them to sustain their hold on territory.
But ISIS never forgot about Iraq.
In January 2014, they took parts of Fallujah and Ramadi in Anbar province, declaring an Islamic State, to little media attention.
In early June, ISIS shocked the world, storming across northern Iraq and capturing Mosul, Iraq's second largest city, with the help of an uneasy alliance of ex-Baathists, tribesmen and other Sunni rebel forces.
On June 29, 2014, the first day of Ramadan, ISIS declared itself a caliphate and Abu Bakr al-Baghdadi as Caliph Ibrahim, and demanded the immediate loyalty of all Muslims throughout the world.
For more information about the Islamic State and its brutal attempt to takeover the world see Clarion Project's Special Report: The Islamic State (ISIS, ISIL)