On a dusty side street in the Shiite holy city of Najaf, arguably the most powerful man in Iraq lives quietly among religious texts, issuing edicts that are strictly obeyed by hundreds of thousands of Iraqis.

Grand Ayatollah Ali al-Sistani has professed no desire for political office, but when he called on the U.S.-led coalition to hold direct elections for an interim government, some 1 million Iraqis took to the streets to protest the American plan.

"Sistani is the only one in this country who can mobilize millions," one Iraqi political leader told Time magazine in 2004. "The Americans shouldn't tempt fate by disregarding that."

Al-Sistani, who speaks with a heavy Persian accent indicating his Iranian birth, has proved he is a survivor, withstanding the official persecution of the Saddam Hussein regime and the political infighting that marked the religious hierarchy in Najaf.

He was born in 1930 in the northwest Iranian city of Mashhad, and was destined for the religious life as his father, grandfather and great grandfather were all renowned religious scholars and leaders.

His family steered him toward a religious education at a very early age. According to his official biography, he began learning the Koran by age 5 and by 1940 had entered Islamic school in his hometown, studying religious texts and laws.

To continue his education he traveled at 19 to the holy city of Qom in western Iran, where he studied under the city's leading Shiite ayatollah. Less than three years later, al-Sistani was on the move again, leaving Iran for one of Shia Islam's holiest cities, Najaf.

Najaf had for centuries served as the preeminent site for Shiite religious scholarship. It is also site to the Imam Ali Mosque, a golden-domed religious site dedicated to a martyred religious leader. There al-Sistani would stay for the next 50 years, focusing on religious studies and doctrines and building a widespread network of supporters and disciples throughout Iraq and the Muslim world.

In Najaf, by all accounts, he continued to excel in his studies, adopting a strict regimen of prayer and living the barest existence -- traits that would remain with him through his rise to religious power. He became a student and disciple of Grand Ayatollah Abul-Qassim Khoei. Khoei, the undisputed leader of Shiites in the city, bestowed upon al-Sistani his belief in so-called "quietism" -- a belief that clergy should focus on the religious, not political, life.

"The clerics must be just like advisers on religious matters and not deal directly with politics," Sayid Ala Azam, a religious student of al-Sistani, told Newsday in 2004. "That's what Sayid Ali Sistani believes. He said we should let the Iraqis choose their own destiny."

Al-Sistani continued to study under Khoei even as his importance and influence grew. By the time he was 31, in the early 1960s, Khoei selected him to be one of two clerics approved to judge religious questions. By the 1980s, the aging Khoei was also clearly grooming al-Sistani as his successor.

By 1989, the 90-year-old Khoei asked al-Sistani to replace him in leading prayers at his mosque. Three years later, when Khoei died, al-Sistani inherited his large, well-financed network. His Persian roots fueled competing claims for the leadership in Najaf, especially from a family of Iraqi-born clerics, the al-Sadrs.

Even as his power grew, al-Sistani faced more threats from the Iraqi government and rival clerics.

Saddam Hussein's regime, dominated by the Baath party and Sunni Muslims, waged a bloody campaign against Shiite leaders. The 1980s and 1990s left hundreds of senior clerics jailed or killed. Ayatollah Muhammad Bakr al-Sadr and his sister were executed in 1980.

Like many other Shiite leaders, al-Sistani was jailed following a regional uprising that erupted following the Iraqi defeat in the first Gulf War. Although he would go through periods of house arrest, the 1991 detention was Saddam Hussein's only direct attempt to imprison the cleric. Helped by his "quietism" beliefs and his lack of ties to Shia resistance groups, he escaped, for the most part, the harsher attacks from the Sunni-dominated Baathists.

But al-Sistani did not escape the violence against Shia clerics. In 1997, two men appeared at his humble house asking to meet with him. Once inside the house they opened fire, killing at least two of the cleric's aides and wounding several others before escaping. Since the attack, the ayatollah, never a highly public figure, receded completely from public view. According to many accounts, he has not left his home since the attack.

Although Saddam Hussein's regime was also pressuring al-Sistani, it was likely Saddam who solidified the cleric’s control of Najaf and many of the Shiite believers when he reportedly ordered the assassination of Ayatollah Muhammad Sadiq al-Sadr and two of his children in 1999.

Now, al-Sistani, at 75, stands as the preeminent "marja" or religious guide for millions of Iraqis; his influence extends far beyond Najaf, with offices in Iran, Dubai, Britain, Syria and Lebanon. He also oversees millions of dollars in scholarships for religious students in Iraq, Pakistan, India, Azerbaijan and elsewhere.

But despite this network of supporters, al-Sistani remains a man rarely seen in public who lives a life that revolves around prayer.

His day begins with evening prayers at 5 p.m., according to Anthony Shadid of The Washington Post. Al-Sistani then dines on a simple meal of olives and cheese while meeting with any guests. He spends the night in prayer and study until the call for dawn prayers. He naps for four hours before rising to conduct business meetings until the noon prayer, and then sleeps for a few more hours before rising to begin again.

Although his life remains simple and minimal, his word is spread through both a network of spokesmen and even the Internet. His site, www.sistani.org, carries both his biography, a searchable outline of Islamic law and his own rulings on matters ranging from interest-bearing loans to the sale of lottery tickets; the materials are posted in English, Urdu, French, Arabic and Farsi.

In the days following the U.S.-led invasion of Iraq, al-Sistani emerged as a voice of moderation, calling for his supporters not to fight coalition forces.

But early on, al-Sistani made it clear he welcomed the overthrow of Saddam Hussein, but did not want the Americans to stay long. He ordered all Iraqis to end any conversation with an American by asking, "When are you leaving Iraq?"

He struck a middle ground between the U.S.-appointed Iraqi Governing Council and the fiery scion of his religious rival, Muqtada al-Sadr. Even as supporters of al-Sadr took up arms, Sistani urged calm, but said he sympathized with the militants’ efforts.

As the U.S.-led coalition and Iraqis work to create a political transition to self-rule, al-Sistani has firmly reiterated that the Iraqi people must select the government.

"The major thing in his mind is not to hand over the country to an American-picked government," senior Islamic party official Mowaffak al-Rubaie told The New York Times. "The fear is that the coalition forces will impose a group of Western-influenced politicians, fanatic liberals who will design the future of Iraq irrespective of the culture and religion of the country."

Al-Sistani, according to his supporters and associates, will continue to focus on ensuring the rights of the Shiite majority in Iraq. It is this determination, coupled with his religious standing among the Shia, which has made the elderly cleric the source of many Iraqis’ hope for a more stable nation after decades of war and oppression.

"He will lead us from hell to heaven," one supporter told the Boston Globe.

-- By Lee Banville, PBS NewsHour