The Confederate line had been shattered and an opening made for expected support. This, however, failed to arrive. General Mott, on the left, did not bring his division forward as had been planned and as General Wright had ordered. The Confederates were reënforced, and Upton could do no more than hold the captured entrenchments until ordered to retire. He brought twelve hundred prisoners and several stands of colors back to the Union lines; but over a thousand of his own men were killed or wounded. For gallantry displayed in this charge, Colonel Upton was made brigadier-general. The losses to the Union army in this engagement at Spotsylvania were over four thousand. The loss to the Confederates was probably two thousand. During the 11th there was a pause. The two giant antagonists took a breathing spell. It was on the morning of this date that Grant penned the sentence, "I propose to fight it out on this line if it takes all summer," to his chief of staff, General Halleck. During this time Sheridan, who had brought the cavalry up to a state of great efficiency, was making an expedition to the vicinity of Richmond. He had said that if he were permitted to operate independently of the army he would draw Stuart after him. Grant at once gave the order, and Sheridan made a detour around Lee's army, engaging and defeating the Confederate cavalry, which he greatly outnumbered, on the 11th of May, at Yellow Tavern, where General Stuart, the brilliant commander of the Confederate cavalry, was mortally wounded. Grant carefully went over the ground and decided upon another attack on the 12th. About four hundred yards of clear ground lay in front of the sharp angle, or salient, of Lee's lines. After the battle this point was known as the "Bloody Angle," and also as "Hell's Hole." Here Hancock was ordered to make an attack at daybreak on the 12th. Lee had been expecting a move on the part of Grant. On the evening of the 10th he sent to Ewell this message: "It will be necessary for you to reestablish your whole line to-night.... Perhaps Grant will make a night attack, as it was a favorite amusement of his at Vicksburg." Through rain and mud Hancock's force was gotten into position within a few hundred yards of the Confederate breastworks. He was now between Burnside and Wright. At the first approach of dawn the four divisions of the Second Corps, under Birney, Mott, Barlow, and Gibbon (in reserve) moved noiselessly to the designated point of attack. Without a shot being fired they reached the Confederate entrenchments, and struck with fury and impetuosity a mortal blow at the point where least expected, on the salient, held by General Edward Johnson of Ewell's corps. The movement of the Federals was so swift and the surprise so complete, that the Confederates could make practically no resistance, and were forced to surrender.