During this combat on the hill, the battle below was raging with great severity. Resolved to break Sickles's centre, and thus wrest the lower ridge (along the Emmetsburg road) from Meade, Longstreet threw McLaws upon the weak point where Birney's alignment bent from the road back toward Round Top. That section of the field became a vortex of fire. Meade, as seemed necessary, in order to maintain his left, put in reinforcements, but all to no purpose. De Trobriand's and Ward's brigades, terribly cut up, were forced in and lost as brigade formations. The brigades of Tilton and Sweitzer, of Barnes's division (Fifth Corps) passed to the front, on their line, and nobly stood their ground until McLaws, having penetrated the centre, took the brigades in flank, when Barnes withdrew his decimated column. To sustain the centre, Humphreys added one brigade from his division, but this reinforcement to Graham's four regiments could not resist the enemy's advance over the road and around his left. Humphreys, therefore, faced about his line, now taken in flank, retired his artillery, and fought, facing south, but still retaining his hold (on his right) on the Emmetsburg road. The contested field was then between himself and Round Top, where the antagonists still struggled.
Caldwell's division, from Hancock's corps, was put into action to stay the Confederate march, after Sickles's centre and left had given way. The two brigades of Cross and Kelly, first skirting the base of Little Round Top, pushed on through the woods into an open field beyond, whence, after a few moments' struggle, they were driven, broken and fearfully cut up. Colonel Cross - a man of astonishing bravery and a zealous soldier from love of his cause - was left dead on the field. Caldwell's second line, composed of the brigades of Brooke and Zook, then advanced and fell upon the enemy with such impetuosity as forced Hood's line back beyond the brook which flows a little to the west of the base of Round Top. It was but a momentary success, however, since, taken in flank by McLaws's advance, Caldwell had to retire. His brigades suffered dreadfully. The gallant Zook was killed and Brooke wounded. Nearly half of their brave fellows were left upon the blood-dyed field. Sweitzer's brigade, having preserved its formation, was pressed in to Caldwell's assistance, but it was hurled back with heavy loss. Ayres's division of regulars - less the brigade of Weed - also moving forward to Caldwell's aid, was met by a flank and front fire which fearfully riddled his ranks, and the regulars retired to their first battle line, well up the ridge, unable to hold the ground below them.
This strife, at the base of Round Top, momentarily ceased, for, having disposed of Sickles's entire left, Lee put Hill into the fight in the endeavor to advance his own centre. Humphreys's right and left, being uncovered, Hancock threw forward a brigade (Willard's) from Hays's division to Humphreys's left, and two regiments to his right. These were not fully in position when Hill's admirably timed attack was made. Taken on front and right flank by Hill, and on the left by McLaws, the division commander had no choice but to retire toward Cemetery Ridge. Sickles, steadying his lines, was stricken down about 6 P.M. having, up to that moment, passed the day's dangers unscathed. The enemy pressed on, under a cutting fire from the ridge crest, but no storm of shot and shell could stay their advancing ranks. Humphreys fell away, contesting every rod of retreat, but leaving gun after gun on the ground with every horse and cannoneer shot away. Hancock, assuming command at Meade's order, directed the more rapid retirement of what was left of the division, and when it reached the cover of the ridge it was but a wreck of regiments - mere gatherings of battalions.
The Confederate leader had played a desperate but skilfully contrived and resolutely executed game. At seven o'clock he found his left and centre thundering at the base of Meade's main line. Could he push his advance further, and gain a lodgement on the ridge, he conceived the field his own and the Federal army defeated. But he was not to witness any further triumph. He had, after all that day's strife, won only a foothold; and though the Fifth Corps (Sykes's), on the extreme Federal left, and the Second Corps (Hancock's), on the centre, had been somewhat involved in the losses, Meade's advantages of concentration were so great that, when the final attempt was made by Lee to gain the crest, he found fresh troops there to meet him. Sedgwick's Corps was sent to the summit of Little Round Top, and to the north of it, to sustain Sykes. Meade, in person, led forward a section of the Twelfth Corps, to fill the weak spot in the line between Sykes and Hancock. Longstreet's column, attempting an advance, had made its way, under cover of woods, well up the ridge, when Hancock discovered the movement and the First Minnesotans were sent to the charge. The enemy broke and fell back in such haste as to lose their regimental colors.
“But seek first his kingdom and his righteousness, and all these things will be given to you as well.”
– Matthew 6:33