state since the 17th and 18th centuries. When the Civil War began in 1861, Petersburg was strategic. The city provided several infantry companies and artillery units to the Confederate Army, along three troops of cavalry. In April 1861 more than 300 free Petersburg African Americans volunteered to work on the fortifications of Norfolk, Virginia under their own leader. Slaveholders also contributed the labor of numerous black slaves. In 1864, Petersburg became a target during the Overland Campaign of Union General Ulysses S. Grant. The numerous railroads made Petersburg a lifeline for Richmond, the Confederate capital. The depot at Pocahontas Island, built for the Richmond & Petersburg rail line, was a transit point for Confederate troops and supplies. Petersburg was the headquarters of the Confederate Army's Second Regiment of Engineers, whose members included Benjamin Morgan Harrod, a Harvard-trained civil engineer who later designed the water and sewer systems of his native New Orleans, Louisiana. After his defeat at the Battle of Cold Harbor, Grant remained east of Richmond and moved south to Petersburg. Grant intended to cut the rail lines into Petersburg, stopping Richmond's supplies. On June 9, troops led by William F. "Baldy" Smith of the 18th Corps, attacked the Dimmock Line, a series of defensive breastworks constructed in 1861 and 1862 to protect Petersburg against the Army of the Potomac under General George McClellan during the Peninsula Campaign. The Confederate troops numbered only 2,000, but Smith and Winfield S. Hancock were hesitant to attack the fortified line. Confederate General P.G.T. Beauregard informed Lee that he was facing virtually the entire the Army of the Potomac with his few defenders at Petersburg. Lee arrived with the fabled Army of Northern Virginia, and the 292-day Siege of Petersburg began. Lee himself admitted that the South could not win a siege war. The trench lines on the east of Petersburg were close together. A soldier in the 48th Pennsylvania Infantry of the Union Army IX Corp, a coal miner in civilian life, remarked, "We could blow that battery into oblivion if we could dig a mine underneath it." Colonel Henry Pleasants, his division commander, liked the idea and forwarded it up the chain of command. Grant gave his approval. On July 30, the explosives in the tunnel were detonated. Due to botched Union leadership and arrival of Confederate General William Mahone, the Union forces suffered a disastrous defeat at the Battle of