Nelson, with a small Union force, was badly beaten by Kirby Smith at Richmond, Ky., August 23, and Louisville experienced the agonies of a panic, for it was practically defenseless. Buell had been so mystified by Bragg's movements that he did not start in pursuit until September 7, and even then might not have reached Louisville in time, had not the Confederate forces lost precious hours in taking Munfordville. But having reached that city, Buell held the key to the situation, and Bragg was forced to retire,--which he did slowly and carefully. At Perryville a portion of Buell's army and some of Bragg's troops met on October 8 in a fierce battle,--an engagement that will always be a source of mystery to students, in that neither side took advantage of obvious opportunities. Bragg, in this campaign, failed of a major object, which was to rouse Kentucky for the Confederacy, though he went through the form of inaugurating a Provisional Governor at the State capital, Frankfort; but he did return South with long trains of fine horses and beeves, with wagons richly laden with food and clothing, and with almost enough recruits to offset the human wastage of his army on march and in battle. Moreover, at the close of the campaign he was in the possession of some territory heretofore held by Federal forces,--territory that was not yielded up until almost a year later. The disorganization in and near Washington,--consequent upon Pope's defeat,--gave Lee an advantage which he improved by celerity of movement; and he was well into Maryland before a Union army was got together to oppose him. The command of this army was entrusted to McClellan, who exercised his customary super-caution, one result of which was that Harper's Ferry, with thousands of prisoners and great stores of military supplies, fell,--with scarce a struggle,--into Lee's hands. This very success might have been fatal to Lee,--for he had scattered his army to accomplish this and other objects,--but McClellan, though fully aware of the situation, moved too slowly, and the Southern general had time to concentrate on the banks of Antietam Creek. Here, on September 17, was fought one of the bloodiest battles of the war,--a battle in which the Confederate Army stood off a foe twice as strong in numbers, and at length retired at leisure, without further molestation. Like Bragg, Lee had failed to win the State that he had invaded, but though he had suffered tremendous losses, he had accomplished some important results.