The 12^th Massachusetts had gone off to the war soon after Fort Sumter to the cheers of blue-blooded Bostonians, with Colonel Fletcher Webster, son of Daniel Webster, riding at it's head. The 12^th included a good many staunch abolitionists in it's ranks, and it had popularized an old revivalist hymn with new words set to it, that told how John Brown's body lay a-moldering in the grave, but his soul was marching on.   It was a superb marching song, and it became widely popular in the Army of the Potomac. (General McClellan found it objectionable and tried to ban it, but the men, especially the New Englanders, sang it anyway).  One day in Washington, the poet Julia Ward Howe heard the soldiers singing it and was inspired to put new words to the measured cadence and create the greatest of all American war songs - "The Battle Hymn of the Republic".

Colonel Fletcher Webster was killed at Second Bull Run.

The 12^th of Massachusetts went on to set foot across "the Corn Field" at the Battle of Antietam on September 17^th 1862 and encountered what the regimental historian called "the most deadly fire of the war".  They lost 224 of 334 men or 67% casualties - the highest casualty rate of any unit that day in the Union Army.  Only 32 men would remain to escort the Regimental Colors from the field to the rear.

The Battle of Antietam was the bloodiest day in American history, bar none. In the first three hours of the battle alone, the Union Army took 8,000 casualties. Twice as many men fell at Antietam in that one day than all the men of the D-day invasion of World War II combined.  "Landscape turned to Red, The Battle of Antietam"

One of the principle sources quoted for this work is the unpublished manuscript of Ezra Ayes Carman in the New York Public Library.  Colonel Ezra Carman led the 13^th New Jersey at Antietam, and later interviewed many survivors from both sides of the conflict and documented their stories. He later served on the Battlefield Board there.