Buell decided at last that his adversary's objective was Nashville, and on the thirtieth of August he gave orders for a retreat toward that place by way of Murfreesboro. At Murfreesboro he made no pause, as by that time Bragg's movement had developed his purpose to go into Kentucky and make a hurried advance upon Louisville, striking that city before Buell could come to its defense. Buell therefore abandoned his march towards Nashville and pushed his column northward by hurried marches, in the hope that he might beat Bragg in the race for the Ohio river, or failing in that, might be in time to fall upon his adversary's rear before he could establish himself in Louisville's defenses. He left a small garrison to hold Nashville but pushed forward in all haste with his main army, in retreat upon Louisville. His retreat was embarrassed at every step. Bragg had forces ahead of him who destroyed bridges, tore up tracks, captured important supply depots, and in one case, at Mumfordsville, compelled the surrender--September 17--of a fortified town with its garrison, upon which Buell had somewhat depended for a reinforcement. At first Buell had left Thomas at Nashville, to defend that city, but his own need of strength became so pressing that he called upon that able officer to join him with the greater part of the troops that had been left at Nashville. What Bragg's campaign really meant, and what he hoped to accomplish by it may best be shown by his own orders and dispatches. On August eleventh, soon after he had established himself at Chattanooga, he sent instructions to General Van Dorn who was confronting Grant at Corinth in which he said: "It is very desirable to press the enemy closely in West Tennessee. We learn their forces there are being rapidly reduced, and when our movements become known, it is certain they must throw forces into middle Tennessee and Kentucky, or lose those regions. If you hold them in check, we are sure of success here; but should they reinforce here so as to defy us, then you may redeem west Tennessee and probably aid us by crushing the enemy's rear." On August 27, just as his army was got into vigorous motion, General Bragg wrote to Van Dorn again as follows: "We move from here immediately--later by some days than expected; but in time, we hope, for a successful campaign. Buell has certainly fallen back from the Memphis and Charleston railroad, and will probably not make a stand this side of Nashville, if there. He is now fortifying that place. General E. K. Smith, reinforced by two brigades from this army, has turned Cumberland Gap and is now marching on Lexington, Kentucky. General Morgan (Yankee) is thus cut off from all supplies. General Humphrey Marshall is to enter eastern Kentucky from western Virginia. We shall thus have Buell pretty well disposed of. Sherman and Rosecrans, we leave to you and Price, satisfied you can dispose of them, and we confidently hope to meet you upon the Ohio."