The movement consisted of Afghans educated at Islamic seminaries in Pakistan and former Islamic fighters, or mujahideen, who opposed the Soviet invasion of Afghanistan. They governed Afghanistan according to a fundamentalist and highly conservative interpretation of Sharia, or Islamic law.
The Taleban - which literally means scholars - emerged in the mid-1990s after being hired by the Pakistani Government to protect convoys trying to open up a trade route between Pakistan and Central Asia.
The group proved effective bodyguards, driving off other mujahideen groups who attacked and looted convoys, and went on to take the southern city of Kandahar.
The Taleban's early campaign against corruption and crime was welcomed by many Afghans who were tired of nearly 20 years of war. They captured Kabul, the capital, in September 1996.
At the time of the 11 September attacks, the Taleban controlled all but the far north of the country.
The US has accused the Taleban of sheltering Osama Bin Laden and the al-Qaeda network. The White House said that the Taleban and Bin Laden had a mutually dependent relationship - with Bin Laden financing the Taleban, and the Taleban making it possible for him to operate.
No evidence has been released proving Taleban complicity in the planning or execution of any of the terrorist operations attributed to Bin Laden.
Nevertheless, some of the suspects held by the US military authorities at a detention facility at Guantanamo Bay in Cuba are believed to Taleban members.