Emerging from a joint AHRC/ESRC-funded project, The Experience of Worship in late medieval Cathedral and Parish Church (2009–13), this doctoral thesis offers a chronological trajectory of the liturgical development of the Mass and Office of the Holy Name of Jesus, and in so doing, seeks to provide fresh perspectives on the significance of the name ‘Jesus’. Jesus Mass was one of a number of liturgies chosen by the project research team to enact as worship, with the texts, chants, spaces, ritual artefacts, vestments and furniture appropriate for the 1530s. My brief was to collaborate with other members of the research team in preparing the Jesus Mass texts and other textual resources for enactments in two different spaces, to participate as a singer in the enactment itself, and to reflect upon the experience after its last iteration. As a result of this high degree of involvement, a possible direction for research presented itself, as summarised below. Section I addresses the wider contextual issues of the devotion to the Holy Name, beginning with a study of the origins and occurrences of the Holy Name in the New Testament. It then traces the later development of the Name as the object of devotion in the West and more specifically in England during the Middle Ages, until it attains an officially recognised liturgical expression in the late fifteenth century. Section II of the thesis then focuses on the emerging Sarum Feast of the Holy Name (7 August) more specifically, with reference to the associated Mass and Office. It offers a survey of the evolvement of the observance through manuscript and printed liturgical sources of Sarum and other Uses, and of the extent of guild activity and musical provision during the period 1480–1530, both indicative of the extent of its practice nationwide. Section III provides an analysis of the emerging themes in both Mass and Office Propers, drawn from a variety of associated sources – scriptural, devotional and theological, which help construct an understanding of the significance of the Name. This is further enriched in Section IV by an exploration of the Feast of the Transfiguration (6 August), celebrated the day before the Holy Name, according to the Sarum Kalendar. In the final section the focus returns to the enactment, and explains the process whereby the Mass texts were transformed into a working edition with text, notation and rubrics, ready to be animated into an act of worship taking place as if in the late Middle Ages, but in 2011.