John Philip Sousa is a famous American composer known for his marches, and this is his most famous song. It's a patriotic anthem, with the stars and stripes referring to the American flag. In his autobiography Marching Along
, Sousa explained that he wrote the song on a boat while returning from a vacation in Europe where he found out that his band manager David Blakely had died. Wrote Sousa: "I was pacing on the deck, absorbed in thoughts of my manager's death and the many duties and decisions which awaited me in New York. Suddenly, I began to sense a rhythmic beat of a band playing within my brain. Throughout the whole tense voyage, that imaginary band continued to unfold the same themes, echoing and re-echoing the most distinct melody. I did not transfer a note of that music to paper while I was on the steamer, but when we reached shore, I set down the measures that my brain-band had been playing for me, and not a note of it has ever changed."