The basis of this thesis is a study of the ninth-century portion of the Liber Vitae of Durham (London, British Library, Cotton Domitian VII). This is a list of names of those who were remembered in the liturgy and prayers of the community of St. Cuthbert, who were resident at Lindisfarne at the time when the greater part of the list was written. The aim of this thesis is to discover what information the Liber Vitae can provide about religion, society, and politics in Northumbria in the seventh to ninth centuries, with particular regard to the role of St. Cuthbert's community in Northumbria. The first part of the thesis is concerned with the Liber Vitae; the second part focuses more on St. Cuthbert's community. Each part consists of three chapters. The first is a description of the manuscript; and the second looks at its purpose, with particular stress on the liturgical aspects of "libri vitae". This chapter also contains a comparison of the Liber Vitae with eight other early commemoration books. The third chapter looks more closely at the information contained in the Liber Vitae, based on the identification of the names in the book. Chapter Four is the first chapter of Part Two and comprises a description and discussion of St. Cuthbert's community and the sites included in its "familia". Chapter Five studies the community's relations with other ecclesiastical centres, and Chapter Six is a discussion of Northumbrian politics in the seventh to ninth centuries and the community's place in this world. Within the thesis certain topics are brought out - the importance of groups within the society of the time, and in particular kinship groups; a study of the royal families who competed for power in Northumbria; the wide range of Lindisfarne's contacts; a reassessment of Lindisfarne's relations with the Irish after 664; and the connection between the Liber Vitae and the promotion of the cult of St. Cuthbert.