The affectionate confidence which existed between Lee and "Stonewall" Jackson till the latter was killed at Chancellorsville had a parallel in the endearing friendship which sprung up between Grant and his principal subordinate, William T. Sherman, who was to bear a hardly less momentous part than his own in the conclusion of the war. Sherman was a man of quick wits and fancy, bright and mercurial disposition, capable of being a delightful companion to children, and capable of being sharp and inconsiderate to duller subordinates. It is a high tribute both to this brilliant soldier and to Grant himself that he always regarded Grant as having made him, not only by his confidence but by his example. As has been said, Grant was required to remain on the defensive between Memphis and Corinth, which mark the line of the Northern frontier at this period, while Buell was advancing on Chattanooga. Later, while the Confederates were invading Kentucky further east, attacks were also directed against Grant to keep him quiet. These were defeated, though Grant was unable to follow up his success at the time. When the invasion of Kentucky had collapsed and the Confederates under Bragg were retreating before Buell and his successor out of Middle Tennessee, it became possible for Grant and for Halleck and the Government at Washington to look to completing the conquest of the Mississippi River. The importance to the Confederates of a hold upon the Mississippi has been pointed out; if it were lost the whole of far South-West would manifestly be lost with it; in the North, on the other hand, public sentiment was strongly set upon freeing the navigation of the great river. The Confederacy now held the river from the fortress of Vicksburg, which after taking New Orleans Admiral Farragut had attacked in vain, down to Port Hudson, 120 miles further south, where the Confederate forces had since then seized and fortified another point of vantage. Vicksburg, it will be observed, lies 175 to 180 miles south of Memphis, or from Grand Junction, between Memphis and Corinth, the points in the occupation of the North which must serve Grant as a base. At Vicksburg itself, and for some distance south of it, a line of bluffs or steep-sided hills lying east of the Mississippi comes right up to the edge of the river. The river as it approaches these bluffs makes a sudden bend to the north-east and then again to the south-west, so that two successive reaches of the stream, each from three to four miles long, were commanded by the Vicksburg guns, 200 feet above the valley; the eastward or landward side of the fortress was also well situated for defence. To the north of Vicksburg the country on the east side of the Mississippi is cut up by innumerable streams and "bayous" or marshy creeks, winding and intersecting amid a dense growth of cedars. The North, with a flotilla under Admiral Porter, commanded the Mississippi