At 7 p.m. on June 15, 1864, the boom of Union cannons to the east foreshadowed an attack on the Dimmock Line. Minutes later, soldiers of the Union Eighteenth Corps broke through the undermanned Confederate line and swarmed over the works at Battery 5. In two hours the Federals captured 1.5 miles of Petersburg’s defenses. Though few Confederates stood between the Federals and the streets of Petersburg, Union Maj. Gen. William F. Smith stopped his advance to await reinforcements. Nine months of tedious, deadly siege passed before the Federals again had such an opportunity to capture Petersburg.