Osama Bin Laden's journey from moderate Islamic youth to ruthless leader of world jihad has been traced in a BBC Two programme that uses only the testimony of people who have actually met the al-Qaeda figurehead.
The life of Osama Bin Laden in the words of those who have met him
Bin Laden was born into a large, extremely wealthy Saudi family. According to Brian Fyfield-Shayler who taught the young Osama English at an elite school in Jeddah, he was taller than his classmates and very good looking.
However he was shy, reserved, too nervous to speak up in class and showed few signs of the extremism that marked his later life.
Other boys would try to convert Mr Fyfield-Shayler to Islam, but he said: "Osama was not one of those, he was not noticeable in his class for his strict religious observance or keenness."
He was happy to learn English - according to his teacher - but unlike many of his half-siblings who were educated abroad and embraced a Western lifestyle, he did not.
Instead Osama stayed in Jeddah where he went to university, to study economics, and first encountered radical Islamic thinkers.
'He adores his mother'
One of the most prominent was the Jordanian Abdullah Azzam who tuned Bin Laden into a glorious Arab past; Saladin the 12th Century vanquisher of the infidel Crusaders should be the students' inspiration, he taught.
Journalist Robert Fisk met Bin Laden in a mountain lair
And when the Soviet Union invaded Afghanistan Bin Laden, then 23, followed Dr Azzam to Peshawar, a frontier town on the Pakistan-Afghan border, to help the Afghan mujahideen liberate their country.
The adult Bin Laden who emerges from the film, is like the boy, shy, softly spoken, outwardly polite and unassuming.
He loves riding and adores his mother. But as one who knows him says - "He is very humble and is very shy, but then on the other hand he's very vicious, he is very vindictive."
His experience in Afghanistan radicalised him further. Initially his role was that of a financier, but he became a fighter and local hero.
A fellow mujahideen Essam Deraz fought alongside him and was amazed that this rich man should choose to throw himself so completely into the fray.
'Prince is a jerk'
He came under the influence of Dr Ayman al-Zawahri an extremist Egyptian with a violent ideology. It was at this point that al-Qaeda changed from being an administrative centre, to a private army dedicated to jihad or holy war.
Bin Laden came under the influence of Dr Ayman al-Zawahri (r)
With the Soviets vanquished, Bin Laden returned to Saudi Arabia but he was not happy with civilian life.
The head of Saudi intelligence, Prince Turki al-Faisel, remembers his amazement at Bin Laden's request to use his mujahideen fighters to overthrow the Marxist regime in neighbouring Yemen.
"The reaction I felt towards his claim that these were his mujahideen was incredulous, and I also realised, that this shy, retiring and seemingly reticent person had changed," he said.
In 1991 Osama left Saudi Arabia for Sudan. Scott Macleod, the first American journalist to interview him, met him then and provides insight into a vain, petty man whose pride was hurt.
"He would say this Prince is a jerk, and this Prince insulted me once. It was actually kind of very local, almost family feud, kind of politics that he would go into."
'A lithe, muscular man'
But Bin Laden's feud was not just with the Saudi royal family. Stripped of his Saudi citizenship, and expelled from Sudan, he had nowhere to go but back to Afghanistan where the chilling nature of his global jihad began to unfold.
The British journalist Robert Fisk was invited to his mountain lair.
After a long, cold journey he was taken to a tent. Osama entered, "like a cat," Fisk said, "A very, very lithe muscular man."
His parting words - spoken four years before 9/11 - sent a shiver down the spine: "Mr Robert, I pray that God permits us to turn America into a shadow of itself."
Most believe that Bin Laden is still alive. When asked by Abdel Bari Atwan, who visited him in Tora Bora, whether he expected to be kicked out of Afghanistan one day, Osama replied: "Yes, and I have my plans."
I Met Osama Bin Laden was broadcast in the UK on BBC TWO, Sunday 28 March at 2000BST