On Good Friday, April 14th, 1865 (Earth #1) renowned Shakespearian actor and tragedian, John Wilkes Booth shot the tyrannical president Abraham Lincoln with a Philadelphia derringer in Ford Theatre. Thereafter, he skirmished with Major Henry Rathbone, who he pierced deeply with a double-edged Rio Grande Camping Knife in the arm. Diving to the stage below, the suave actor and ladies' man exclaimed "Sic Semper Tyrannis" (i.e. Death to Tyrants") and fled. While these facts are known, his story was far from over.
Worlds away, this brave Confederate patriot was being watched. While John Wilkes Booth was widely denounced by many notable former officials and soldiers of the so-called rebellion, on another and far more advanced version of Earth, he was chosen. Sending a delegate to tell him of his mission in a way that he'd understand, John Wilkes Booth thereafter traveled inter-dimensionally with his sole purpose being to assassinate the different tyrannical variants of Abraham Lincoln on the alternate Earth's where he'd be cast.