The purpose of the Confederates was to break through the left of Grant's line and reach the river, thus placing themselves on their enemy's flank, threatening his rear and imperiling his entire army. General Albert Sydney Johnston had been mortally wounded early in the afternoon, but Beauregard, upon whom the Confederate command had devolved, adopted and sought to carry out the strategy determined upon. Late in the afternoon, he hurled the whole of Bragg's force upon the left of Grant's line with an impetuosity which must have achieved success had the tremendous assault been made an hour earlier. But fortunately for the Federals General Buell had come up with a part of his army. He quickly threw such regiments as he had with him into action at the point of danger, and the danger was really extreme. It was only necessary for the Confederates to push Grant's left wing back for about two hundred yards farther than it had been pushed already in order to seize upon the landing and completely cut Grant off from his gunboats and transports acting as ferry-boats, and from all hope of further reinforcement. In that case Grant's problem would have been to save his shattered army from complete overthrow, with surrender as the well-nigh inevitable result. There is little doubt that the left wing must have given way before Bragg's assault, as the Confederates expected it to do, but for the reinforcement which Buell sent into action at the critical moment. This reinforcement saved the left wing from the destruction intended for it. This statement is made upon the very careful and trustworthy authority of General Van Horne, writing under direct inspiration of General Thomas. In his "Memoirs" General Grant repudiates the claim of Buell's having rendered important assistance at that time and insists that he rendered him no help of any consequence on the first day of the battle. But the memoirs were written from the memory of a very ill man many years after the event, and may therefore be erroneous. At any rate General Van Horne's account of what happened, supported as it is by copies of all the orders given, seems the more trustworthy authority on the point at issue. Night was now near at hand. During a long day of continuous and desperate fighting Grant had been slowly beaten back to the neighborhood of the river bank. There he stood at bay with all his artillery and all his infantry massed in a commanding position, shattered and broken, and standing in desperate defense of a point from which he could retreat no farther without retreating into the river. Across his front lay a deep ravine. This would have been difficult for his enemy to cross under the best of conditions. It was rendered the more difficult by the fact that it was in part filled with back water from the river. Still more important was the fact that it was completely commanded by a plunging fire from the Federal artillery which in spite of defeat stood resolutely to its guns.