John Philip Sousa was an American composer and conductor of the late 19th and early 20th centuries. He is known as 'The March King' for his military marches, which were widely performed in the United States and internationally. He also composed waltzes, cakewalks, and other forms of light classical music. He wrote more than 130 marches, many of which are still popular today. He was a major figure in the development of the modern American concert band.