Answer: TRUE.
In November 1862 Burnside was ordered to take charge of the Army of the Potomac after McClellan was relieved from duty. He reluctantly accepted "the offer" and immediately ordered a bold advance toward the Confederate capital of Richmond. Burnside met with heavy delays in crossing the Rappahannock River, which allowed General Lee to assemble his Army of Northern Virginia outside the town of Fredericksburg. In the ensuing
battle, Burnside’s forces made a series of failed frontal assaults against Lee’s nearly impregnable defenses, resulting in a decisive Confederate victory and almost 13,000 Union casualties. Burnside attempted to rally his demoralized army for a second offensive, but the plan, later known as the Mud March was thwarted by heavy rains and failed to materialize.