The 35-year-old is a poor public speaker but holds enormous influence over mainly poor Shi'ites in Baghdad and Basra.
Has Sadr always been an enemy of the Baghdad government?
Sadr's rise was opposed by the US-led authority in Iraq. His newspaper was banned in 2004 for spreading hatred and an arrest warrant was issued against Sadr.
He boycotted the 2005 election but his allies won a substantial number of seats.
How is the Mahdi army seen in Iraq?
The Mahdi army spearheaded the worst fighting of Iraq's civil war. Its fighters now dominate eastern Baghdad and swathes of its western districts, areas which have been cleansed of Sunni Muslims.
What has the ceasefire achieved?
Gen David Petraeus, the American commander in Iraq, recognised that the move could dramatically curtail US military casualties. US spokesmen were instructed to draw the distinction between "responsible" followers of Sadr, who suspended fighting, and "special groups" of Shi'ite guerrillas
clipped from: www.telegraph.co.uk 