They crossed the Potomac at a ford below the mouth of the Antietam, then crossed the Antietam on the lowest bridge back into the peninsula, and without waiting for orders rushed upon the Northern flank.
The attack was so sudden and fierce that Burnside's entire division reeled back.

Here, as in the north, the face of the battle had been changed in an instant.

Not only could Colonel Winchester mourn over those lost two days, but he could mourn over every lost half hour in them.

Had Hill come a half hour later Lee's whole center would have been swept away.
Lee and his great lieutenants, Jackson and Longstreet, were still confident.

Despite the disparity in numbers they had beaten back every attack.
A.P.Hill was a man who corresponded in fire and impetuosity to Hooker.
The number of his veterans was not so great, but their rush was so fierce, and they struck at such a critical time that the Northern brigades were unable to hold the ground they had gained.