Iraq's Shiites make up nearly 60 percent of the country's predominantly Muslim population, but until the overthrow of Saddam Hussein, were among the most repressed. They number 16 million, are overwhelmingly Arab and live mostly in southern and central Iraq
While Shiites make up a majority of the population in Iraq, they belong to a minority sect of Islam, encompassing roughly 15 percent of Muslims worldwide and often discriminated against by the dominant Sunni sect.
The branches disagree about who succeeded Islam's prophet Muhammad after his death in 632. Shiites believe religious authority should have gone to Muhammad's son-in-law, Ali, and 11 of his descendents.
The slaughter of some of these Shiite successors or "imams" by the ruling caliphs 13 centuries ago led the sect to idealize suffering and martyrdom more than its Sunni counterpart.
The friction today between Shiites and Sunnis is especially palpable in Iraq, where elements of the minority Sunni population are waging an insurgency against the U.S.-led coalition and now politically dominant Shiites.
Under Saddam, Sunnis were the rulers and administrators. Shiites, on the other hand, were sent to the front to fight fellow Shiites in neighboring Iran during the two countries' 1980-88 war.
Shiite uprisings against Saddam were brutally suppressed. His forces executed thousands of Shiites and buried them in mass graves.
The Shiite faith's roots are in Iraq, but Iraqi Shiites are closely aligned with Iran, with which they share religious, cultural and social ties.
(c) 2005, Knight Ridder/Tribune Information Services.