The argument that has underpinned much of this book has been the idea of Nielsen as a modernist composer. The definition of modernism upon which this claim rests, however, is far from monolithic or one-dimensional. On the contrary, modernism emerges repeatedly from this discussion as a highly contested category: it can be identified as a term of frequent abuse in early twentieth-century music criticism (especially in the contemporary reception of Nielsen's more challenging large-scale works), and subsequently emerges as a complex, problematic strand in recent music-historical writing. Jørgen I. Jensen's image of the double man, of Nielsen as both ‘great little Dane’ and as continental European modernist, is an eloquent example of the ways through which the idea of modernism in Nielsen's music can be refracted: both outwards, towards a cosmopolitan internationalism, and inwards, towards the invented, highly localised notion of Denmark as in some senses an autonomous, culturally closed domain. As analysis has shown, Nielsen's work in fact engages powerfully with broader strands in early twentieth-century European music. Like Mahler, his works are often fractured and energised by moments of gennembrud or Durchbruch, a sense of radical destabilisation created through the incursion of music from seemingly beyond the boundaries of the individual musical work. Such moments in Mahler, according to Adorno, constitute a fundamental critique both of the symphonic project and of its wider artistic and cultural environments.