In May, 1861, the Union troops moved into Virginia and occupied Arlington Heights and Alexandria. On June 1 an engagement at Fairfax Court House between a company of Union cavalry and Confederate troops resulted in the loss of six Union and twenty Confederate soldiers. The Union forces under General McDowell occupied the town of Fairfax about the middle of July, inaugurating the first Bull Run Campaign. The battle of Bull Run was fought July 21, 1861. After the first battle of Bull Run, a systematic plan for the defense of the National Capital began to take shape. At that time the commanding heights four miles west of Alexandria and six miles from Washington were occupied by the Confederates, Falls Church being the headquarters of General Longstreet. In October, 1861, the hills were again taken possession of by the Union troops. The system of works for the defense of Washington on the south began with Fort Willard below Alexandria, and terminated with Fort Smith opposite Georgetown, comprising in all twenty-nine forts and eleven supporting batteries, besides Forts Ethan Allen and Marcy at the Virginia end of Chain Bridge, with their five batteries of field guns. [Illustration: Mr. Charles A. Marshall] Falls Church was the most advanced post of General McDowell's corps, when on August 3, 1861, a correspondent of Harper's Weekly writing from here to that paper described the old Church as it appeared at the beginning of the Civil war as follows: "On this page we illustrate Fall's Church, Fairfax County, Virginia, from a sketch by our special artist with General McDowell's 'corps d'armee.' This is the most advanced post of our army in Fairfax County, and has been the scene of several picket skirmishes. Falls Church was built in 1709, and rebuilt, as an inscription on the wall informs us, by the late "Lord" Fairfax, whose son, the present "Lord" Fairfax, is supposed to be serving in the rebel army. The title of "Lord," we may observe, is still given to the representative of the family. The inscription on the old church reads as follows: [Illustration: Mr. John S. Garrison] 'Henry Fairfax, an accomplished gentlemen, an upright magistrate, a sincere Christian, died in command of the Fairfax Volunteers at Saltillo, Mexico, 1847. But for his munificence this church might still have been a ruin.' Service was held in the old church two Sundays since, Rev. Dr. Mines, Chaplain of Second Maine Regiment, officiating, and most of the troops in the neighborhood being present."