Addressing concepts about documentary heritage in the light of Library and historical concepts and understanding the importance of musical collections as part of social memory, these are some of the themes addressed in the following study. The Major Xavier Torres Music Band of the fifth battalion of the military police of the state of Ceará and the Alberto Nepomuceno Music Conservatory are the institutions addressed for this work and the relevance of their collections as part of the documentary and musical heritage of the city of Fortaleza.