At the end of 2012, Sunni tribes in Iraq's Anbar province began a series of protests that lasted throughout 2013.
The initial demand was for the release of Sunni prisoners; the imprisonment of women was a major grievance in the male-dominated culture of Anbar.
It quickly escalated into wider anti-government protests that were initially welcomed by many across the political spectrum.
Shia religious leaders including the Grand Ayatollah Ali Sistani and Muqtada al-Sadr publicly acknowledged Sunni grievances and Shia tribal leaders visited the demonstrations to express their solidarity.
The prime minister, Nouri al-Maliki took note of the concerns and tried to push through a list of reforms in January 2013, but he was blocked by both Shia political parties and some Sunni parties.
The Sunni tribes in Anbar saw the move as a provocation.
The events were followed in April 2130 by the formation of an armed group - Islamic State of Iraq and the Levant - that waged a bloody campaign across Baghdad and beyond.
The group took advantage of the power vacuum caused by the lack of communication between Baghdad and Anbar, allowing ISIL fighters to form safe havens and criss-cross the Iraqi-Syrian border.
The group played on Sunni fears of Shia domination and the Anbar tribes unofficially accepted their presence.
In December 2013, ISIL fighters defeated a whole faction of the Iraqi army and prompted Maliki to send troops into the towns of Ramadi and Fallujah to break up the protests.
One of the main Sunni tribal leaders in the province, Sheikh Ahmed Abu Risha, decided to back government forces against ISIL, but another sheikh, Hatem Ali Sulieman, supported the armed group.
The government encouraged the tribes to fight ISIL themselves, but a lack of consensus among senior figures prevented the Iraqi army from entering Fallujah.
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