Louis Armstrong - History Maker Bios Author:Judith Pinkerton Josephson True or False? Louis Armstrong was often called "The World's Greatest Trumpet Player." True! Louis Armstrong changed the sound of American music with his exciting, powerful trumpet-playing. He helped make jazz one of the world's most popular forms of music. And his gruff singing voice and shining personality made him one of the most popular ente... more »rtainers of all time.« less