For a short time General Buckner was kept a prisoner at Fort Warren until he was exchanged. But the friendship between the two leaders continued. When General Grant, after having been twice President, failed in his business career, Buckner sent him a check, trusting that it might be of use in his time of trouble. Grant, shortly before his death, wrote his old-time comrade and antagonist requesting that Buckner do him the final honors by becoming one of his pallbearers. [Illustration: BUCKNER, THE DEFENDER OF DONELSON.] SHILOH--THE FIRST GRAND BATTLE No Confederate who fought at Shiloh has ever said that he found any point on that bloody field easy to assail.--_Colonel William Preston Johnston (Son of the Confederate General, Albert Sidney Johnston, killed at Shiloh)._ In the history of America many battles had been fought, but the greatest of them were skirmishes compared with the gigantic conflicts of the Old World under Marlborough and Napoleon. On the field of Shiloh, for the first time, two great American armies were to engage in a mighty struggle that would measure up to the most important in the annals of Europe. And the pity of it was that the contestants were brethren of the same household, not hereditary and unrelenting enemies. At Fort Donelson the western South was not slain--it was only wounded. The chief commander of that part of the country, Albert Sidney Johnston, determined to concentrate the scattered forces and to make a desperate effort to retrieve the disaster of Donelson. He had abandoned Bowling Green, had given up Nashville, and now decided to collect his troops at Corinth, Mississippi. Next in command to Johnston was General Beauregard who fought at Bull Run, and who had come from Virginia to aid Johnston. There also came Braxton Bragg, whose name had become famous through the laconic expression, "A little more grape, Captain Bragg," uttered by Zachary Taylor at Buena Vista; Leonidas Polk who, though a graduate of West Point, had entered the church and for twenty years before the war had been Episcopal bishop of Louisiana, and John C. Breckinridge, former Vice President of the United States. The legions of the South were gathered at Corinth until, by the 1st of April, 1862, they numbered forty thousand. Meantime, the Union army had moved southward and was concentrating at Pittsburg Landing, on the Tennessee River, an obscure stopping place for boats in southern Tennessee, and some twenty miles northeast from Corinth. The name means more now than merely a landing place for river craft. It was clear that two mighty, hostile forces were drawing together and that ere long there would be a battle of tremendous proportions, such as this Western hemisphere had not then known.