By 1861, the divergent sympathies of a border state had divided the members of the regiment. While most of them supported the Southern cause, and succeeded in making their way out of Baltimore when it passed under Union military control in April 1861, others served in the Union Army. In June, 1861, the Southern sympathizers organized the First Maryland Infantry, CSA, at Harpers Ferry and became part of Thomas "Stonewall" Jackson's Corps which fought the first Battle of Manassas. During the Valley Campaign in 1862, the town of Front Royal, Virginia was defended by Federal troops from Maryland. Upon receiving this information, General Jackson ordered, "Maryland to the Front," to lead the attack. In this action the First Maryland Infantry (CSA) defeated the First Maryland Infantry (USA) at the Battle of Front Royal. They followed that victory with a rout of the Pennsylvania Bucktail Rifles at Harrisonburg on 6 June 1862, earning from Major General Ewell the honor of carrying a "buck tail" on their colors.