This week in 1861.. Robert E. Lee paced the room. Events proceeded quickly. And he knew his next decision would change everything for him, his family, and history.

A week ago, Confederates attacked Fort Sumter in South Carolina. President Lincoln issued a proclamation and called for a 75,000-man militia to quell the insurrection. Lincoln even asked Virginia to send men and asked Robert E. Lee to take command of the Union Army.

And this is how Lee came to this moment of pensive pacing at Arlington House.