The Battle of Antietam played out like three separate battles, with major action happening in distinct areas at different parts of the day.
The beginning of the battle, in the early morning, consisted of a stunningly violent clash in a cornfield which would become famous.
Soon after daybreak, Confederates troops began to see lines of Union soldiers advancing toward them as if on parade. The Confederates were positioned among rows of corn. Men on both sides opened fire, and for the next three hours the armies battled back and forth across the cornfield.
Thousands of men fired volleys of rifles and batteries of artillery from both sides raked the cornfield with grapeshot. Men fell, wounded or dead, in great numbers, but the fighting continued. The epic struggle in the cornfield became legendary, known as the bloodiest part of America's bloodiest day.
For much of the morning the fighting seemed to focus on the ground surrounding a small white country church erected by a local pacifist sect called the Dunkers.
Gen. Joseph Hooker Was Wounded and Carried From the Field
The Union commander who had led that morning's attack, Major General Joseph Hooker, was shot while on his horse and carried from the field. He recovered and later described the scene:
"Every stalk of corn in the northern and greater part of the field was cut as closely as could have been done with a knife, and the slain lay in rows precisely as they had stood in their ranks a few moments before.
"It was never my fortune to witness a more bloody, dismal battle-field."
By late morning the slaughter in the cornfield came to an end, but action in other parts of the battlefield continued.