In this report, American Lt. Col. George Armistead described a bombardment that continued, largely unabated, for 25 hours. When Francis Scott Key, an American lawyer watching the battle from behind the British lines, saw that the American flag was still waving over Fort McHenry on the morning of September 14, he knew the fort’s defenders had prevailed. He was so moved by their heroism, he wrote a poem, whose words became our national anthem on March 3, 1931.