sentences:  Of great significance was Nielsen's contribution to the 1922 publication, " Folkehøjskolens Melodibog (The Folk High School Songbook)", of which he was one of the editors together with Thomas Laub, Oluf Ring and Thorvald Aagaard.The book contained about 600 melodies, of which about 200 were composed by the editors, and was intended to provide a repertoire for communal singing, an integral part of Danish folk culture.The collection was extremely popular and became embedded in the Danish educational system.