After marching north down the Shenandoah Valley, the Confederate army of Lt. Gen. Jubal A. Early crossed the Potomac River into Maryland on July 5, 1864 headed for Washington D.C. On July 9, a makeshift Union force under Maj. Gen. Lew Wallace attempted to stop Early along the Monocacy River, just east of Frederick. Wallace, joined by another division sent north from the Petersburg lines, was outflanked and defeated after putting up a stiff resistance. After defeating Wallace, Early continued his advance towards the Federal capital. Wallace’s defeat at Monocacy bought time for more reinforcements to bolster the defenses of Washington.