Bragg's plan of battle was to fall upon the Federal left, crush it, bend back the line, and place himself between the Federal army and its base. There could have been no better plan of battle formed, but it was not executed in the best fashion possible. Had Bragg fully realized the superiority of Longstreet to his other corps commanders, and still more the superiority of Longstreet's men who had fought at Fredericksburg, Chancellorsville, Antietam and Gettysburg, he would have placed Longstreet upon his right, in order that the blow might be delivered with all that was possible of crushing force. Instead of that he assigned the force of General Leonidas Polk to that position. Polk was a West Point graduate, but soon after graduation he had become a clergyman of the Episcopal church, and for many years past had been a bishop in that church. A fact that had more importance perhaps, was that Polk's men had not been trained by the experience of Lee's tremendous onslaughts to the best work of the soldier, and unfortunately for Bragg, but fortunately for Rosecrans, that left wing of the Federal army upon which the main assault was made, was under command of General George H. Thomas, one of the most determined fighters on either side during the war. Under Polk the assault was made loosely, and without that perfect concert of action which Longstreet, had he been in command, would have brought to bear. Thomas met it with obstinate resistance, and when opportunity offered, with counter attacks that greatly interfered with Bragg's plans. Nevertheless, the fighting was obstinate and destructive to both sides. In the end Polk succeeded in forcing Thomas's line backwards for a time, but before nightfall the Federal general had recovered the greater part of his ground, and when the first day's fighting ended the position of the two armies was practically the same that had existed in the morning.