This joint Liturgical Study is concerned with the relationship between the development of pneumatology and the liturgical invocations of the Holy Spirit in the early church, and to this end the author considers two case studies. The first study considers the Sacramentary of Sarapion alongside the doctrinal works of Athanasius, particularly focusing on his Letters to Sarapion. The second turns to the anaphoral tradition ascribed to Basil of Caesarea, and considers these in relation to his dogmatic writings, especially De Spiritu Sancto. The Study has particular regard to the context in which the chosen theologians wrote and the liturgical texts developed, and the comparisons of the texts are made accordingly. In the first case study, the strength of the similarities of approach suggest that ascription to Sarapion is not unreasonable. In the second, the complexities of the developmenr of the liturgical text mean it is difficult to isolate a relationship to the dogmatic material. This historical investigation aims to inform present debate through the exploration of historical relationships between liturgy and theology, and to enhance the understanding of the historical foundations of the question.