When the Saints Go Marching In, often referred to as "The Saints", is an American gospel hymn. Though it originated as a Christian hymn, it is often played by jazz bands. This song was famously recorded on May 13, 1938 by Louis Armstrong and his Orchestra.
In the Barney franchise, it was used as the tune for Walk Across the Street, The Marching Song, and Oh, When We March. It was also used as an underscore in Barney's Band.