A misconception has developed that the 20th Massachusetts of Pierce's brigade in Gibbon's division stopped Mahone's rolling up of II Corps' front line on June 22, 1864. The truth is that Mahone's three brigades broke down under the weight of prisoners they took. The person in the best position to know was Capt. Henry Lyman Patten of the 20th's Company E, who commanded the 20th that day. He wrote shortly afterward:
“The affair on which the papers have so puffed your humble servant was not by any means of the importance which has been attached to it.
“The truth was the Rebs made no attack of any consequence on the 20th. I was ready for them if they should. But they did not attempt seriously, if at all, to dislodge me. I am inclined to believe that a very little resistance, or even show of resistance, such as I made, would have stopped them anywhere in our Brigade. But the regiments on my left were completely surprised. It was very hot, the troops were utterly exhausted by their unparalleled hardships, and the first some of them, - as I am told, - knew of the matter, was waking up and finding themselves gobbled beyond escape.
“You must remember it was in the middle of the day, hotter than tophet, the line was in thick woods, and our men had begun to believe that Johnny Reb was never going to attack again.
“The most serious fault rests with some General, - I don’t know who, - who so disposed his troops that the enemy got square in the rear of the left of Gibbon’s division, unopposed. Some say it was Birney’s fault and some whisper Meade.
“There may have been some troops who behaved badly, but they were not the 15th or 19th Mass….”Letter, H. L. Patten to “Dear Col.,” July 10, 1864. Association of Officers of the 20th Massachusetts Volunteer Infantry, “Reports, letters & papers appertaining to 20th Mass. Vol. Inf. (Boston, Mass.: Boston Public Library, 1868), 234-235.