In 1981, Ayman al-Zawahiri was sentenced to three years in prison in connection with an assassination attempt on Egyptian president Anwar Sadat.  The attack was carried out by the Egyptian Islamic Jihad (EIJ), a terrorist organization influenced by the Muslim Brotherhood.

After he was released from prison, Zawahiri fled to Saudi Arabia in 1985, and the following year moved to Pakistan. In Pakistan, Zawahiri set in motion his plans to take over and reorganize EIJ, whose primary goal was to violently overthrow the Egyptian government.

In Pakistan, Zawahiri met Osama bin Laden, who was providing resources to Maktab al-Khadamat (MAK), a terrorist organization he created with Dr. Abdullah Azzam to fight Soviet forces in Afghanistan. By the mid 1990s, Zawahiri and bin Laden merged their economic resources, manpower and tactical expertise. This relationship helped Zawahiri become the second emir of the EIJ, where he directed a campaign of terror against the Egyptian government.

In 1992, Zawahiri traveled with Bin Laden to Sudan. Following a failed attempt to assassinate the Egyptian President Hosni Mubarak, EIJ and its Al Qaeda affiliates were expelled from Sudan in 1996, taking refuge in Afghanistan.

Al Qaeda officially absorbed EIJ in February 1998, when Zawahiri and bin Laden issued a joint fatwa titled, "World Islamic Front against Jews and Crusaders."  The fatwa, which called for war with Israel, Jews, western culture and western ideals, advocated killing "Americans and their allies, civilians and military," and liberating "Al Aksa Mosque and the Holy Mosque from their grip."

Soon after the fatwa was released, Al Qaeda attacked the U.S. embassies in Nairobi, Kenya, and Dar Es Salaam, Tanzania, killing 212 people and 12 people, respectively.  Over 4000 people were wounded in the two attacks.  In the following years, Al Qaeda escalated its terrorist activity against the U.S., attacking the U.S.S. Cole in Aden, Yemen, and carrying out the September 11 terrorist attacks.

The toppling of the Taliban regime in Afghanistan by American and coalition military forces in response to the September 11 attacks, forced Zawahiri, bin Laden and some of their top lieutenants to go into hiding.  In recent years, Zawahiri has increasingly become the public voice of Al Qaeda, issuing dozens of statements on behalf of the terrorist movement.