While the two sects share the same basic beliefs, differences in hierarchy and doctrine make Catholics and Protestants an apt comparison.
In remarks likely to worsen Baghdad's already difficult relationship with the Kurds, Iraqi Prime Minister Nouri al-Maliki said Wednesday the Kurdish self-rule region was harboring Sunni militants.
The discovery of the bodies has reawakened fears of sectarian violence that wracked the country in the mid 2000s.
The video was purportedly filmed on Friday and would be the first public depiction of Abu Bakr al-Baghdadi, the militant group's leader.
The video purports to show Abu Bakr al-Baghdadi, who is the leader of the Sunni insurgent group that has launched powerful insurgencies in Iraq and Syria.
Prime Minister Nouri al-Maliki vowed Friday to fight until the 'Islamic State' militants are defeated. The new Iraqi parliament ended its first session after failing to name his replacement.
Iraqi Kurdistan is moving ahead with independence plans. With Kurds also holding an important swing vote in Iraq's parliament, this is a problem. A big one.
Iraqi Prime Minister Nouri al-Maliki also offered amnesty to Sunni militants during a televised speech to the nation Wednesday.
The first shipment of ground attack Sukhoi fighters comes after Iraq complained the US wasn't delivering support its needs to fend off Islamic militants.
Militant Sunni insurgents fought off Iraqi military forces in Tikrit and issued an international call for allegiance, Sunday.
The Iraqi military launched an attack on insurgents in Tikrit with a multi-pronged assault spearheaded by ground troops backed by tanks and helicopters.