We left Buell's army at Nashville. It remained there from February 25 to March 15, 1862, when his cavalry started for Savannah, where the Army of the Tennessee was then partially assembled under General C. F. Smith. Halleck had, March 4th, relieved Grant from any active command in the field, and ordered him to place Smith in command of the "expedition," and himself to remain at Fort Henry. Grant chafed much under this treatment, and repeatedly asked to be relived of further service under Halleck. Grant's recent success at Forts Henry and Donelson, and his exceptional character for assuming responsibilities and fighting, led to a public demand for his restoration, which reached Washington and Halleck, and forced the latter, on the 13th of March, to restore him to the command of his army and district. Grant reached Savannah on the 17th of March, and found Smith fatally ill, and a portion of the troops already at Pittsburg Landing on the west bank of the Tennessee. He subsequently ordered other divisions to the Landing, and although the question of intrenching was considered, his chief engineer officer, Colonel (afterwards Major-General) James B. McPherson, reported against the necessity or practicability of employing the raw troops in constructing defensive works. It was decided the undisciplined and undrilled soldiers (as most of them were) could be better prepared for the impending campaign by drilling them. Grant made his headquarters at Savannah (east of the Tennessee), leaving Sherman in charge of that portion of the army in front of Pittsburg Landing. Besides some troops of Buell's army who were left to hold Nashville, Mitchel's division was detached to operate on a line through Murfreesboro south into Alabama or to Chattanooga, as might seem best. McCook's division left Nashville March 16th, following the cavalry, and other divisions of Buell's army followed at intervals. At Columbia, Tennessee, McCook was detained, reconstructing a burned bridge over Duck River, until the 30th. Nelson reached this river, and by fording crossed his division on the 29th, and was then given the advance. Buell did not hasten his march nor did Grant, it would seem, regard his early arrival important. The purpose was to concentrate the Army of the Ohio at Savannah, not earlier than Sunday and Monday, the 6th and 7th of April. Nelson's division reached there the evening of the 5th, of which Grant had notice. Buell arrived about the same time, but did not report his arrival, or attempt to do so until 8 A.M. the 6th, when Grant had gone to Pittsburg Landing to take personal command in the battle then raging with great fury.