Through the day, the battle between Heth’s men and the First Corps forces see-sawed back and forth but was largely a stalemate. But in the early afternoon, the situation changed. MG Rodes’ Division arrived from the north. They occupied an area of high ground just to the north and west of the city, known as Oak Hill. But here, too, Rodes made a tactical error. Instead of sending in his infantry he chose to bring up his artillery to ‘soften up’ the Union line. All this really did was alert the Union commanders to his presence. They managed to shift some of the right flank units to face north. When they did finally attack, his three brigades did so in an uncoordinated fashion and each was driven back in turn.
Almost simultaneous with Rodes arrival, the Union Eleventh Corps under MG Howard was entering the fray. He moved his corps through the city and began taking up positions north of Gettysburg thereby extending the Union line far to the east. Another nearly overlooked clash took place when one of his regiments moved forward to occupy a hilltop in front of the main Union line. These men were quickly attacked from three sides and were nearly wiped out. It seemed as if Union units had a propensity to act on their own and place themselves at great risk.
About 4PM two uncoordinated events took place that finally decided the outcome of the Day 1 battle. In the west, at the angle where the Union line turned east, Heth’s left flank and Rodes’ brigades managed to coordinate a two-pronged attack that hit the Union line like a tsunami wave. At the same time, MG Early’s Division was marching in on the far right Union flank. The Union units there were newly arrived and had yet to firmly establish their positions. Early quickly shifted from marching to attack formation and smashed into these unprepared units.
From east to west, then north to south, the Union line began to crumble. Eleventh Corps units fell back into the city in disarray. Seeing their right flank unprotected, First Corps units also began to fall back. Some into the city; others in a more orderly fashion headed south to the cemetery rally point. Reynolds’ orders were being carried out hours after his death. It was as if the Union line was being unzipped!
Far to the south, a second brigade of Pender’s Division were forming up to launch an attack on the left flank of the Iron Brigade. Before they were completely in position, the Iron men simply stood up and marched away as if they were on parade. They fell back into the city en route to the cemetery.
Had Col Perrin’s Rebel brigade advanced to follow the Iron men, he might very well have disrupted the movement of the Union forces as they emerged out of the south end of the city. In addition, he would have forced the Iron Brigade to make a slower fighting withdraw. Had Perrin captured Union men as they made their way towards the cemetery the Union strength might have been greatly reduced.