This study's thesis is that instances of pastoralism in the works of Frank Bridge from 1914 to 1930 demonstrate a gradual darkening of his pastoral vision, and evince his increasingly complex relationship with the genre of pastoral music that flourished in English music in the early twentieth century (referred to in this study as 'the English pastoral tradition'). The study traces the change from the sensual and romantic idyll of Summer (1914-15), through progressively more ambiguous and darker manifestations of pastoral, and eventually to a bleak anti-pastoral vision in Oration (1930). This trend reflects Bridge's increasingly ambivalent relationship with the English musical establishment, his own radical change of musical language during these years, and significant changes in his personal circumstances. It also reflects the decline of romanticism and the rise of modernism in English music, a paradigm-shift that happened around the time of World War I, considerably later than in the music, literature and visual art of continental Europe. Chapters 1 to 3 examine the English pastoral tradition from three different contexts. Chapter 1 suggests that the English pastoral tradition may be understood as a genre, and describes a number of 'family resemblances' that run through and characterise it. Second, the English pastoral tradition is placed in the context of pastoral art from Classical times to the twentieth century, with a focus on pastoral in English literature. Finally, chapter 3 examines the social and cultural context of the English pastoral tradition and explores resonances between English society in the early twentieth century and the meaningstructures that underpin pastoral. The remaining chapters comprise a series of analytical discussions of six of Frank Bridge's works: Summer (1914-5), the first of the Two Poems (1915), Enter Spring (1926-7), There is a willow grows aslant a brook (1927), Rhapsody-Trio (1928) and Oration (1930). While a variety of analytical techniques are employed, the approach is broadly semiotic and focussed on musical meaning. Each analysis traces the relationships between signifying structures in the works and various musical and non-musical strands of the contextualising cultural discourse. As a result the works become the starting points for relatively wide-ranging discussions in which pastoralism in the music of Frank Bridge is understood as a site at which ideas of English nationalism and international modernism engaged with one another. Frank Bridge's place in this discourse, as revealed in the analyses of his works, becomes increasingly ambivalent and modernist.