John Singleton Mosby started with nine cavalrymen from the Cavalry command of General J.E.B. Stuart on detached duty in Loudoun and Fauquier counties in early January 1863. Stuart supplied several more men two weeks later. Mosby had immediate success with surprise attacks against the Union cavalry screen and its many small outposts on the Loudoun-Fairfax county line. This led men home on leave, boys ages 16 and 17, infantry convalescent’s, and a limited number of transfers from Stuart’s command to join the Rangers. The force grew in size until some 1,911 men had served under Mosby.
Mosby’s unit was formalized as the 43rd Battalion of Virginia Cavalry on June 10, 1863, in the parlor of the Rector House at Rector’s Crossroads (today’s Atoka). While one of only two units allowed to remain partisans in the Confederate Army, they took orders directly from President Davis, General Robert E. Lee, and Stuart. Usually, their goals were to demoralize the Union cavalry screen west of Washington and to attack supply trains, wagon trains, and outposts. In 1864-65, many of the Rangers’ raids focused on the northern Shenandoah Valley.
These “partisan” Rangers were allowed to keep what they took from Yankees. Mostly they took pistols, carbines (short repeating cavalry rifles), and horses. Most of the Rangers possessed four pistols and four horses to be always ready and well armed for a raid with a fresh horse. Other materiel was sold to the Confederate Army or given to homeowners who took the risk of boarding rangers locally.
Mosby's Rangers relied on a number of sympathetic homeowners throughout "Mosby's Confederacy" who opened their doors to partisans. These safe houses dotted the landscape and allowed Mosby's men to melt away into the countryside whenever Union forces conducted scouts through the area. The Rangers also relied on civilians for supplies, especially food and horses. Some supplies came willingly from Confederate sympathizers, but Mosby and his men also took what they needed from the region's Unionists as well. This burden fell especially hard on the Quakers of the Loudoun Valley. In response to Mosby's raiding Union cavalry descended on the Loudoun Valley in November 1864. Their orders were to carry off or destroy whatever forage or livestock could be used to feed Mosby's men. The "Great Burning Raid" fell heavily on both Confederate and Union sympathizers throughout the region. One Quaker girl living in Waterford encouraged the destruction, shouting "'Burn away, burn away, if it will keep Mosby from coming here."