The thesis focusses on how music has been mythologised in different ways. Mythologisation refers to the ways in which a given phenomenon – in this case music – is connected and invested with ideas and stories that ultimately cannot be substantiated as they characteristically deal with “religious” issues and questions in the sense that they have no empirical answers and thus necessitate believing while there may be overwhelming evidence against them. In the thesis, mythologisation of music is addressed in relation to the postsecular attempts to rescript the sacred, by paying specific attention how different conceptualisations of the “popular” and the “sacred” become interrelated. Thus, the treatment is predominantly theoretical in nature and linked to a broader interest in the intersections of the popular and the sacred in music. The analysis does not focus on religious popular music, or popular music and religion, but on a more conceptual level on how different apprehensions of the popular and the sacred become operationalised and politicised in musical situations. On the basis of existing research within ethnomusicology and the philosophy of music, mythologisation of music is divided in the thesis into four general categories: first, origins of music, detectable not just in the ubiquity of cosmological explanations in various epics and indigenous mythologies but crucially also in the hard-core neuroscientific approaches to music; second, music’s autonomy, based on widespread assumptions about music as a transcendent or supernatural power of its own, with certain universal traits and inexorable effects; third, individuals with allegedly exceptional musical propensities, whether labelled as stars or geniuses; and fourth, authenticity, particularly in relation to presumptions about pureness and excellence. Methodologically, the thesis builds on the cultural study of music and anthropology and sociology of religion. Through socio-constructionist discourse analysis the categories of mythologisation of music are examined in relation to the multidimensionality of the popular and the sacred. Regarding the popular, at issue are its quantitative, aesthetic, sociological, folk, partisan and postmodern dimensions; the sacred in turn is examined in terms of religious, subcultural, national, economic and political aspects. The analysis reveals that the dimensions of the popular that become emphasised in mythologisation of music are the aesthetic, folk and postmodern ones, while on the sacred side it is the cluster of subcultural, national and economic facets which is connected to all areas of mythologisation of music. All five aspects of the sacred have however a fairly equal footing in the ways to mythologise music, which is somewhat unsurprising given the close connection between myths and the sacred in the general sense. With respect to the popular in turn, the conspicuous links between myths about individuality in music and quantitative and mass cultural dimensions are notable. Moreover, the findings indicate that overall the discourses of autonomy and authenticity carry a paramount weight when considering the intersections of the popular and the sacred in mythologisation of music.