Here is a video of "When the Saints Go Marching In" played by a jazz band with Louis Armstrong on trumpet and vocals. Louis Armstrong is one of the best known jazz musicians from America. He is famous for playing trumpet. Legend has it that he earned his nickname from the unique way his cheeks puffed out when he played. Some people thought it looked like his mouth was a satchel (a bag), so they started calling him "Satchel Mouth", which was shortened to "Satchmo," a nickname he is still recognized by.