General Halleck had arrived at St. Louis on November 18, 1861, to take command of the Western Department.  Perhaps a more energetic commander would have been found ready to cooeperate with Farragut at Vicksburg by the end of June, 1862; for matters had been going excellently with the Unionists northeast of that place, and it would seem that a powerful and victorious army might have been moving thither during that month.  Early in March, however, General Halleck reported that Grant’s army was as much demoralized by victory as the army at Bull Run had been by defeat.  He said that Grant “richly deserved” censure, and that he himself was worn out by Grant’s neglect and inefficiency.  By such charges he obtained from McClellan orders relieving General Grant from duty, ordering an investigation, and even authorizing his arrest.  But a few days later, March 13, more correct information caused the reversal of these orders, and March 17 found Grant again in command.  He at once began to busy himself with arrangements for moving upon Corinth.  General Buell meanwhile, after sustaining McClellan’s rebuke and being taught his place, had afterward been successful in obtaining for his own plan preference over that of the administration, had easily possessed himself of Nashville toward the end of February, and was now ready to march westward and cooeperate with General Grant in this enterprise.  Corinth, lying just across the Mississippi border, was “the great strategic position” at this part of the West.  The Mobile and Ohio Railroad ran through it north and south; the Memphis and Charleston Railroad passed through east and west.  If it could be taken and held, it would leave, as the only connection open through the Confederacy from the Mississippi River to the Atlantic coast, the railroad line which started from Vicksburg.  The Confederates also had shown their estimation of Corinth by fortifying it strongly, and manifesting plainly their determination to fight a great battle to hold it.  Grant, aiming towards it, had his army at Pittsburg Landing, on the west bank of the Tennessee, and there awaited Buell, who was moving thither from Nashville with 40,000 men.  Such being the status, Grant expected General A.S.  Johnston to await in his intrenchments the assault of the Union army.  But Johnston, in an aggressive mood, laid well and boldly his plan to whip Grant before Buell could join him, then to whip Buell, and, having thus disposed of the Northern forces in detail, to carry the war up to, or even across, the Ohio.  So he came suddenly out from Corinth and marched straight upon Pittsburg Landing, and precipitated that famous battle which has been named after the church of Shiloh, because about that church the most desperate and bloody fighting was done.