19 Jan 2001 United Nations ban on military aid to Afghanistan takes effect
29 May 2001 Four Al Qaeda associates convicted for role in African embassy bombings
Jun 2001 U.S. warns Afghanistan that its government will be held responsible for attacks by terrorists sheltered by Afghanistan
6 Aug 2001 Taliban arrests 24 foreign aid workers, including two American women, in Afghanistan on charges of spreading Christianity
21 Aug 2001 CIA asks FBI to find al-Midhar and Alhamzi; they are not located, and will hijack Flight 77 on 11 September
Aug 2001 Osama bin Laden threatens "unprecedented attacks" against the U.S.
9 Sep 2001 Ahmed Shah Massoud, leader of Northern Alliance, seriously injured in car bombing assassination; he dies days later
10 Sep 2001 Osama bin Laden's deadline for his deputies to return to Afghanistan
I wonder about the details here - I recall hearing he was killed by someone posing as a journalist whose camera contained a bomb.