This thesis argues that the congregational or collective singing of metrical psalms was one of the principal means through which ordinary men, women and children negotiated the religious changes that shook sixteenth-century England. The thesis argues that these otherwise ‘voiceless’ individuals (those who, while using their voices to sing, lacked agency within their parish community, and are thus largely silent in the sources) shaped both the practice and corpus of texts and tunes to fit their preferences, and in doing so shaped both the speed and spread of Protestantism’s introduction into England, making its arrival and its ideas more palatable for themselves. To study fully the singing of metrical psalms, however, historians must appreciate the musical element which lies at the heart of this phenomenon. Without doing so, they miss some of the central reasons for its popularity and success. This thesis, therefore, establishes a framework through which historians can use music as a historical source, analysing it as it was heard by contemporaries. Drawing on the work of scholars from fields as diverse as music, theology, philosophy, and poetry, the thesis introduces three approaches which form the central pillars for this framework. Adopting this framework allows us to gain a fresh understanding of the surviving sources, revealing that the singing of metrical psalms may represent the most significant means through which the otherwise ‘voiceless’ came to accept Protestantism. The thesis also argues that the singing of metrical psalms was both more widespread and less controversial than scholars have previously understood, especially during the overlooked Edwardine and Marian periods. During Elizabeth I’s reign, in large part due to the experience of music and the agency of the otherwise ‘voiceless’, metrical psalmody firmly and quickly established itself first in London, then further afield, becoming an immovable element in congregational worship