Osama bin Laden was born into one of Saudi Arabia's most prosperous families but chose a path to fanaticism, inspired an organisation that led to a new brand of global terror, and ultimately became the most wanted man in the world.
The biggest manhunt in history finally caught up with bin Laden, whose money and ideas inspired the September 11 attacks on the United States, which killed almost 3,000 people.
To his enemies he was the epitome of evil, a man who had brought mass murder to the United States, the Middle East, Europe, Africa and East Asia. But to his supporters he was a hero who went from fighting the Russians in Afghanistan to leading an unending jihad against the United States and Arab governments he deemed as infidels.
His actions set off a chain of events that led to wars in Afghanistan, and then Iraq, and a clandestine war against extremists that touched scores of countries.
Bin Laden's al Qa'eda organisation has been blamed for the 1998 bombings of two US embassies in Africa and the 2000 attack on the USS Cole in Yemen, as well as numerous other plots, some successful and some foiled.
Perhaps as significant was his ability - even from hiding- to inspire a new generation of terrorists to murder in his name. Most of al Qa'eda's top lieutenants have been killed or captured in the years since September 11 but intelligence officials in Europe and Asia say they now see a greater threat from homegrown radical groups energised by bin Laden's cause.
Al Qa'eda is not thought to have provided logistical or financial support to the North African group behind the March 11, 2004, bombings in Madrid, which killed 191 people, or the four British Muslim suicide bombers who killed 52 people in London on July 7, 2005.
But these events were inspired by bin Laden's vision of a global jihad.
Bin Laden was born in Saudi Arabia in 1954. His father, Mohammed, had arrived in Jeddah from Yemen as a young man and rose from a penniless immigrant to the millionaire head of a massive construction firm. Mohammed had close links with the Saudi royal family and his company's crowning achievement was to rebuild Islam's holiest mosque in Mecca. Bin Laden's Syrian mother was Mohammed's 10th wife.
Bin Laden became the most pious of the sons among his father's 54 children. Unlike many of his brothers he stayed in Saudi Arabia for his education, studying management and economics at university in Jeddah.
His path towards militancy began as a teenager in the 1970s when he got caught up in the fundamentalist movement then sweeping Saudi Arabia. At King Abdel Aziz University, the student who was brought up as a Salafi was exposed to more politicised ideas.
He became interested in the Muslim Brotherhood and studied the two radical scholars Muhammad Quttub and Abdullah Azzam, who would later become one of his mentors.
Thin, bearded and more than 6 feet tall, bin Laden graduated in 1979, the year of the Iranian revolution and the Soviet invasion of Afghanistan - the first focus of his newfound idealism.
Inspired by the initial resistance to the Russian occupation, bin Laden started raising funds, recruiting fighters and spending time in the Pakistani city of Peshawar, a staging point for mainly Arab militants who had arrived to fight the Russians across the border.
In the mid 1980s he moved to Peshawar where he continued to help raise money. Bin Laden's own involvement in the actual fighting is thought to have been greatly exaggerated.
At the time, bin Laden's interests converged with those of the United States, which backed the mujahideen against Soviet occupation with money and arms.
The eventual defeat and departure of the Soviet army was seen as a glorious victory, and persuaded bin Laden not to disband the network of financiers and recruits he established.
When bin Laden returned home to Saudi Arabia, he was showered with praise and donations and was in demand as a speaker in mosques and homes.
A seminal moment in bin Laden's life came in 1990, when US troops landed on Saudi soil to drive Iraq out of Kuwait.
Bin Laden tried to dissuade the government from allowing a "non-Muslim" army into the kingdom, but the Saudi leadership turned to the United States to protect its vast oil reserves. When bin Laden continued criticising Riyadh's close alliance with Washington, he was stripped of Saudi citizenship and expelled.
"I saw radical changes in his personality as he changed from a calm, peaceful and gentle man interested in helping Muslims into a person who believed that he would be able to amass and command an army to liberate Kuwait. It revealed his arrogance and his haughtiness," Prince Turki, the former Saudi intelligence chief, said in an interview with Arab News and MBC television in late 2001.
Bin Laden took his four wives and 10 children to Sudan. In five years there he consolidated the operations of his group - now known as al Qa'eda - and joined forces with Ayman al Zawahiri, an Egyptian militant who became his deputy.
Bin Laden left Sudan in 1996, around the same time that Western intelligence agencies began to link al Qa'eda to attacks on US forces in Saudi Arabia.
When the Taliban - who would eventually give him refuge - first took control of Kabul in September 1996, bin Laden and his followers kept a low profile, uncertain of their welcome under the new regime. The Taliban leader, Mullah Mohammed Omar, called bin Laden to southern Kandahar from his headquarters in Tora Bora and eventually through large and continual financial contributions to the Taliban, bin Laden became dependent on the religious militia for his survival.
According to the official US 9/11 inquiry, the CIA estimated that as many as 20,000 militants trained in al Qa'eda's Afghan camps before September 11.
In a 1997 interview with CNN bin Laden clearly stated his goals.
"We declared jihad against the US government, because the US government is unjust, criminal and tyrannical," he said.
On August 7, 1998, powerful truck bombs outside the US embassies in Kenya and Tanzania killed 224 people.
It was al Qa'eda's first major international attack.
Days later, bin Laden escaped a cruise missile strike on one of his training camps in Afghanistan launched by the United States in retaliation.
The September 11 attacks were allegedly masterminded by Khalid Sheikh Mohammed, who had been personally approved by bin Laden, who selected the attackers.
After the US-led invasion toppled the Taliban from power a massive manhunt for bin Laden, who had a bounty of $25 million (Dh91.8) on his head, got underway.
But he could not be found in the punishing mountain terrain along the Afghan and Pakistan border. During the past decade, bin Laden and his deputy al Zawahiri have appeared regularly in audio and video tapes to issue threats, and comment on a wide range of current events, although the appearances trailed off in recent years.
As his years in hiding dragged on, bin Laden became less and less of a presence. Revolutions and upheaval in the Middle East and North Africa in recent months were largely inspired by young people seeking economic and political freedom, rather than bin Laden's radical vision of an Islamic caliphate.
Through it all, bin Laden vowed repeatedly that he was willing to die for his cause.
"America can't get me alive," bin Laden was quoted as saying in an interview with a Pakistani journalist conducted shortly after the US invasion of Afghanistan.
And while his bluster proved prophetic, in the end it was not bin Laden who would get the last word.
"On nights like this one," Barack Obama said in announcing bin Laden's death to the world, "we can say to those families who have lost loved ones to al Qa'eda's terror: Justice has been done."
* With reporting by the Associated Press and Agence France-Presse