In 1931, the Star-Spangled Banner became the United States national anthem. It is based on the poem Defense of Fort M’Henry, written on September 14, 1814 by Francis Scott Key while he was held captive on the British frigate Surprise during their failed attack on the fort in Baltimore. Key penned the words on the back of an envelope after seeing the huge flag – 42ft long, with 7 white stripes, 8 red stripes and 15 white stars – still standing after the attack. Prior to 1931, the anthem was My Country ‘Tis of Thee,” which had the same melody as Britain’s national anthem God Save the Queen, which is based on music written by John Bull in 1619. Bull’s melody has been used more than any song in national anthems. The British anthem was performed the most times in a single performance. In 1909, while waiting for King Edward VII who was getting dressed, a German band played the anthem 17 times.