"Ewell, we need to go to Gettysburg. The Union army has a new Commander"
"Right away General Lee!"
General Lee learns that the Union has a new commander and tells General Ewell to move the troops towards Gettysburg. But what Lee didn't know was how close the Union troops were to Gettysburg.
Lee sent some of his troops into Gettysburg, they ran into a Union Cavalry triggering the Battle of Gettysburg. The Confederate's General Longstreet believed that the Union was impossible to overrun while Lee believed the confederacy was invincible.