When someone makes music, the content of their music-making is the song they sing, or the piece they play. The idea of musical content is sometimes analyzed in terms of the notion of a type whose tokens occur when that content is played or sung. Such an analysis can be associated with different assumptions about the ontology of types. I consider four such assumptions; and I argue they give rise to four different conceptions of musical content. Finally, I consider the question what kind of unity is possessed by musical content on these four different conceptions.