The thesis examines how religious memory permits the medieval prisoner to redeem himself textually from any potential shame associated with his imprisonment through the creation of a self-promotional, autobiographical discourse. By combining his interest in his spiritual affairs with his experiential memory of his recent past, the prisoner presents himself as a virtuous Christian, deserving of God's reward. This work not only demonstrates how the prisoner utilises memory to justify the actions or beliefs engendering his downfall, but it also considers how this reified sense of self-perception prompts the incarcerated writer to think upon his salvation prospects. Thus I argue that memory is inextricably linked to the construction of an autobiographical narrative in which the prison-writer ponders his past, present and future identity. Throughout the thesis, the multiple sub-genres that constitute prison-writing are illuminated as I demonstrate how each prisoner suggests his virtue by inscribing his self-reflective thought into a religious genre, including hagiography, biblical letters, Passion mediations and penitential prayer. In the Introduction, I draw attention to the need for scholars to recognise the existence of the medieval subject, who is often denied ontology in studies of the history of selfhood. I also discuss the need to develop the current understanding of pre-modern autobiographical inscription by examining the mnemonic practices and strategies that underpin this form of writing. Moving on from here, the thesis examines six late-fourteenth and fifteenth-century narratives to show the different ways in which acts of recollection legitimise identity in the medieval prison. Chapter One explores the creative and political function of memoria by showing how two Ricardian traitors, Thomas Usk and William Paris, compare their own experience of imprisonment to that of a virgin martyr as they set about reframing their reputations for treachery. As Richard himself used hagiographic commemoration to promote his kingship, this act permits Usk and Paris to respectively appeal to and critique the king, who is responsible for their imprisonment. Chapter Two examines two prose epistles that were written by the Wycliffite preachers, Richard Wyche and William Thorpe. By considering how both men frame their memory of persecution in a narrative structure which emulates the epistle format deployed by medieval popes, as well as the prison epistles that St Paul wrote to the early Church, I argue that Wyche and Thorpe use their letters to entreat the recently formed Lollard community to stand firm in her faith, even if she is threatened with death. Chapter Three also considers how the prison-writer seeks to inspire a community outside the prison. Here I argue that the orthodox writers, John Audelay and George Ashby, both imprint a memory of the prisoner in the minds of the reader so that this latter figure will remember to cleanse her own soul of sin by showing mercy to the imprisoned community. The prisoner is thus shown to be nothing less than a conduit to divine grace. Throughout this thesis, religious memory, which is combined with experiential memory, is shown to be integral to the construction of the late medieval prison-writers past, present and future autobiographical identity.