Dom Stephen Moreno OSB (1889-1953) was one of Australia’s most respected and prolific composers of church music in the early twentieth century. He lived for almost fifty years in the Benedictine Community at New Norcia, WA, and composed 210 works, comprising over 1100 individual compositions and over 200 accompaniments to Gregorian chant. The majority of his output was in liturgical sacred music, including Masses, motets and Litanies, but it also included a significant quantity of secular vocal and instrumental music. Much of Moreno’s music was written for the Benedictine Community of New Norcia but he also composed liturgical music for the broader Australian church and secular music for the wider Australian community. Less than a quarter of Moreno’s music was published, and the vast majority of his output survives in manuscript at New Norcia. The purpose of the present study is to define the extent of Moreno’s output, to establish its chronology, and to examine the contexts and purposes for which he composed. This study has significantly added to and revised the findings of previous studies of Moreno’s music undertaken by Ros (1980) and Revell (1990) and supplies a revised biography. Approximately thirty-five percent of the works included in this study are identified and discussed here for the first time. Of the previously known works, Ros specifically dated less than one quarter and the present study refutes some seventy-four percent of Revell’s dates. Through the investigation of important primary sources, including the composer’s surviving correspondence and the Chronicle of the Benedictine Community, this study provides for the first time a complete chronology and contextual account of Moreno’s entire oeuvre. This has involved the cataloguing and indexing of over ten thousand pages of Moreno’s manuscripts and more than five thousand pages of his personal correspondence. This study has also identified a number of compositions unique to collections outside of New Norcia. While the primary purpose of this study has been to establish an accurate chronology and historical context for each work, the opportunity has also been taken to provide a preliminary assessment and discussion of Moreno’s musical style and compositional methods. Note: “Due to the inclusion of third party copyrighted material we are unable to mount the entire thesis. It can however be viewed at St Patrick’s Campus Library by prior arrangement.”