Lexington, VA., 15 April, 1868.
William M. McDonald, Cool Spring, near Berryville, Clarke Co., Va.:
My Dear Sir -- I thank you for your kind letter of the 3d instant, which I have been unable to answer till today. I hope that your school history may be of such character as will insure its broadest circulation, and prove both interesting and instructive to the youth of the whole country. . .
. . . As to the battle of Gettysburg, I must again refer you to the official accounts. Its loss was occasioned by a combination of circumstances. It was commenced in the absence of correct intelligence. It was continued in the effort to overcome the difficulties by which we were surrounded, and it would have been gained could one determined and united blow have been delivered by our whole line. As it was, victory trembled in the balance for three days, and the battle resulted in the infliction of as great an amount of injury as was received and in frustrating the Federal campaign for the season.
Very respectfully and truly, yours,
R. E. Lee.
Source: Annals of the Civil War
Commentary
In this letter to William McDonald written after the war, Robert E. Lee comments on Gettysburg and offers his general opinion on why the battle was lost by the Confederates.