John Wilkes Booth

 was the actor who assassinated U.S. President Abraham Lincoln in Ford's Theatre in Washington, D.C. on 14 April 1865. (BFA: Assassin in the Limelight)

Both Aaron Eddowes, the would-be Lincoln assassin foiled by the Fifth Doctor in Richmond, Virginia on 9 April 1865, and Will Johnson were known to have mentioned Booth's complicity after the fact. (TN: Blood and Hope)