The Taleban are a hardline Islamic movement fighting a guerrilla-style campaign in Afghanistan.
They controlled much of the country in the late 1990s and imposed an authoritarian regime that followed strict Sharia, or Islamic, law.
They were removed from power by US-led forces after the 9/11 attacks in the US because of their support for Osama Bin Laden, the leader of the al-Qaeda network.
The Taleban emerged as a fighting force in late 1994 under the leadership of Mullah Mohammad Omar.
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At the time, Afghanistan was torn by clashes between feuding warlords known as mujahideen, who fought each other after defeating a Soviet invasion.
The Taleban pledged to restore peace and stability and introduce Sharia law.
They captured the Afghan capital, Kabul, in 1996 and by 1998 had taken control of almost 90% of the country.
Taleban forces as they fled Kabul
The Taleban were popular with many Afghans because of their success in stamping out corruption and improving security.
But their hardline Islamic regime stripped away many women's rights and punished religious offences very severely.
On the diplomatic front, only three countries recognised the Taleban regime as Afghanistan's legitimate government.
They included neighbouring Pakistan, where many Taleban members had been educated in madrassas (religious schools).
Many other countries strongly criticised the Taleban's human rights record.
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But the main source of conflict with the international community was the Taleban's ties with Osama Bin Laden.
Bin Laden was a guest of the Taleban in Afghanistan and many al-Qaeda members trained in the country.
The attacks of 11 September led the US to repeat its demands for the Taleban to hand over Bin Laden.
The Taleban refused and a US-led offensive began on 7 October 2001. By early December, the Taleban regime had collapsed.
Although the Taleban were forced to flee Kabul, their leader Mullah Omar survived, along with Bin Laden and other senior figures.
Their retreat allowed them to limit their number of casualties and material losses.
Five years since losing power, resurgent Taleban forces have been involved in increasingly bloody attacks on Nato troops.
The violence is particularly rife in parts of southern and eastern Afghanistan, where the Afghan government is struggling to extend its authority.
Scores of foreign and Afghan troops and large numbers of civilians have been killed, as well as some aid workers.
Foreign forces, meanwhile, say they have killed hundreds of insurgents.