Five months after Union troops were slaughtered charging Marye's Heights, Sedgwick's corps finally stormed the same stone wall — this time breaking through in minutes.
The Second Battle of Fredericksburg (May 3, 1863) was fought on the same killing ground as the December 1862 disaster — but with reversed fortunes. This time a smaller Union force under General Sedgwick successfully stormed Marye's Heights, the fortified ridge that had repulsed fourteen Union charges just months before.
Lee had left only about 12,000 men under General Jubal Early to hold Fredericksburg while marching west to fight Hooker at Chancellorsville. Sedgwick's much larger VI Corps had been ordered to break through and march to Hooker's relief — a mission that would require taking the heights that had broken the Army of the Potomac in December.
A first Union assault on the Confederate center failed. Then Union soldiers noticed what appeared to be an unguarded Confederate flank — and in a remarkable twist, a Confederate colonel granted a ceasefire to retrieve casualties, unwittingly allowing Union officers to closely reconnoiter his own position.
Sedgwick's second assault using all three VI Corps divisions swept the ridge. The 5th Wisconsin and 6th Maine were first over the stone wall that had been so impenetrable in December. Confederate losses were only 700 men, but the symbolic fall of Marye's Heights sent shockwaves through Lee's army.
The victory was strategically incomplete. Early retreated south while Cadmus Wilcox's brigade slowed Sedgwick's westward advance toward Chancellorsville. When Lee learned of the breakthrough, he immediately detached two divisions eastward — weakening his grip on Hooker — to deal with Sedgwick's threat.
The Second Battle of Fredericksburg is often overshadowed by Chancellorsville, but it demonstrated that the stone wall defenses that had seemed invincible in December were not, in fact, invincible — and showed how decisively battlefield conditions could change when the defending force was a fraction of its original strength.