During the Civil War, retaliation for alleged atrocities against civilians escalated between the two sides. During his 1864 Maryland invasion, Confederate Gen. Jubal A. Early demanded that several towns pay ransoms or be burned in revenge for Union Gen. David Hunter's destruction of houses in the Shenandoah Valley. After returning to Virginia, Early sent Gen. John McCausland north to demand a ransom from Chambersburg, Pennsylvania; when its residents refused, McCausland burned the town on July 31. Union troops then arrived in time to prevent the burning of Hancock, Maryland, and McCausland retreated toward Virginia. Withdrawing from Folck's Mill on August 1, 1864, his force met Union troops at the canal bridge here, drove them back toward the Potomac River, and flanked them out of breastworks and two houses, forcing them to flee across the river to Green Spring Station on the Baltimore & Ohio Railroad. There, a blockhouse with 100 men and a train carrying a rifle car for infantrymen and an Iron Clad armored artillery car guarded the station, and fire from the train and cannons pinned down the Confederates along the river. McCausland responded by moving a cannon to Alum Hill and firing on the train; the first shot struck the locomotive's boiler and disabled it, and later shots forced the Federals to abandon the Iron Clad and rifle car and flee. McCausland then demanded the surrender of the blockhouse from Col. Israel Stough, commander of an 82-man detachment of the 153rd Ohio Infantry. Outnumbered 30 to 1, Stough surrendered on the condition that his men be immediately paroled with their personal property, McCausland agreed, and the Federals marched west. The Confederates destroyed railroad property and continued withdrawing to Romney and Moorefield.