The guy who killed Abraham Lincoln.
Abraham Lincoln was shot in the back of the head by Booth at Ford's Theater only days after the Civil War ended. It was part of a conspiracy by Southern extremists that hoped to reignite the war.
Lincoln's death came with massive indirect side effects and led the North's fury against the South. Lincoln's assassination was actually more troublesome for them since Lincoln had in many ways a better plan for Reconstruction. This change in power led to Radical Republican domination during Reconstruction.
He was an actor famous in his own right. "This is kind of like if President Obama was shot by Brad Pitt or something" -- Mr. Bowman. Just makes things crazier.