General Bragg, on arriving at Corinth, wished to attack the troops as they were beginning to land at Pittsburg and Crump's landings. General Beauregard forbade this, writing to Bragg: "I would prefer the defensive-offensive--that is, to take up such a position as would compel the enemy to develop his intentions, and to attack us, before he could penetrate any distance from his base; then, when within striking distance of us, to take the offensive and crush him wherever we may happen to strike him, cutting him off, if possible, from his base of operations or the river." On March 25th, Johnston completed the concentration of his troops. Van Dorn was in person in Corinth, and was ordered to bring forward his command. Johnston determined to wait as long as practicable for it. Meanwhile, to hasten the organization and preparation of his army, he appointed Gen. Bragg chief of staff for the time, but to resume command of his corps when the movement should begin. Of him, Colonel William Preston Johnston says, in his life of his father--a valuable book, prepared with great industry, and written with an evident desire to be fair: "In Bragg there was so much that was strong marred by most evident weakness, so many virtues blemished by excess or defect in temper and education, so near an approach to greatness and so manifest a failure to attain it, that his worst enemy ought to find something to admire in him, and his best friend something painful in the attempt to portray him truly." A thorough disciplinarian and a master of detail, his merits found full play, and his defects were less apparent in his position on the staff. Johnston was organizing his army; Grant was assembling his twenty-three miles away. On the other side of the Tennessee, ninety miles from Savannah, Buell, halted by Duck Creek, was building a bridge for his troops--a bridge which it required twelve days to construct. Johnston having completed his concentration, it was his obvious policy to attack before Grant should be further reinforced. General Beauregard, in his letter of March 18th to Bragg, said: "While I have guarded you against an uncertain offensive, I am decidedly of the opinion that we should endeavor to entice the enemy into an engagement as soon as possible, and before he shall have further increased his numbers by the large numbers which he must still have in reserve and available--that is, beat him in detail." Lee wrote to Johnston, on March 26th: "I need not urge you, when your army is united, to deal a blow at the enemy in your front, if possible, before his rear gets up from Nashville. You have him divided, and keep him so, if you can." It was Johnston's purpose, and expressed, to attack Grant before Buell should arrive. But he determined to continue organizing and waiting for Van Dorn as long as that would be safe.