“The defining moment in [militant Islamist] Ayman al-Zawahiri’s life occurred on October 6, 1981, with the assassination of [Egyptian President] Anwar Sadat. …It transformed him from an agitator and critic of the Egyptian government to a spokesman for revolutionary violence, even if it meant the murder of a head of state.”

 – Bruce Riedel, The Search for Al Qaeda, Page 19