I have a letter, passed down through my family, written by my gr-gr granduncle, Henry Shildt of the 6th Wisc. Inf. It was written in March of 1862, " near Centreville, Va." He mentions of the Federal Army's march into Northern Virginia. He also mentions the famous Quaker Guns ( but he doesn't call them by that name ) which were logs painted black and placed into breastworks to look like artillery. Sometimes an actual field piece was mixed in with them to keep the Yankees on their toes.