Virginia (August 9, 1862) during the opening of the Northern Virginia Campaign. Ordered to destroy a railroad bridge at Mitchell's Station on August 15, they next guarded the Union Army's rear as it retreated across the Rappahannock River, and then rendered support to Union artillery batteries during the First Battle of Rappahannock Station (August 22–August 25) before moving on to operations associated with the Battle of Thoroughfare Gap (August 28). After fighting in the Second Battle of Bull Run (August 28–30) and Battle of Chantilly (September 1), they were reassigned to the Maryland Campaign under Major-General Joseph Hooker, and then fought again in the Battle of South Mountain (September 14). Three days later, while fighting with his regiment in the Battle of Antietam on September 17, 1862, William Paul performed the act of valor which later resulted in his being awarded the U.S. Medal of Honor. When the 90th Pennsylvania's color-bearer and two other members of his regiment's color guard unit were killed in action “under a most withering and concentrated fire,” according to his award citation, he retrieved the regiment's colors and continued to carry and protect that flag for the remainder of the intense fighting which raged that day. In recalling those events for an interviewer years later, Paul said: During the battle of Antietam, our corps was being vigorously attacked in a wooded and hilly part of the country, where our forces could not very well cope with an enemy accustomed to bush fighting. Nevertheless, in a hard and deadly struggle we were slowly but surely driving the enemy back, when Color-Sergeant Mason, who was in advance of our lines some four or five yards, cheering us on, was shot. A rebel detachment immediately rushed forward to capture the fallen colors. Seeing this, I placed myself at the head of a few men, probably ten in number, and charged out to meet the enemy, and if possible rescue the colors. We clashed with a shock, and a sharp hand-to-hand fight ensued in which two of our men were killed and five so severely wounded, that they were unable to be of any assistance. A rebel had already seized the colors, but I grasped them and with one supreme effort wrenched the precious banner from his hold. Waving it high above my head, I carried it throughout the remainder of the battle. In the melee my comrades managed