This chapter examines the arc of jihadist militancy in South Asia since 9/11. It suggests that Al-qaeda’s attack on the United States achieved a crucial objective of militant Islamists: driving a wedge between the ‘West’ and the ‘Islamic world’. The chapter suggests that 9/11 had the same effect upon South Asia as the Battle of Teutoburg Forest had on relations between ancient Rome and Germanic tribes. The two events share important similarities, despite having occurred nearly two millennia apart. In both cases, a provocative and unexpected attack, enabled by stealth tactics, resulted in an irreparable breach between a previously advancing and ‘civilizing’ imperial power and a ‘barbarian’ people unwilling to accept an alien culture being imposed on them. On both occasions, a flurry of punitive actions followed, but eventually gave way to resentful disengagement and a lasting siege mentality on the part of the imperial power.