...s had the First Corps in place of Hooker (wounded). These two (the First and Ninth) were still under Burnside's direction. The new troops promised from the defenses of the capital were commanded by Sigel , Heintzelman, and Bayard, the latter having only one division of cavalry. General Sumner's command was immediately divided. The Twelfth Corps was left behind to guard the fords of the Upper Potom...