A debate which has concerned many liturgists in the last 100 years such as Jungmann, is the question of the existence of a separate early Irish Eucharistic liturgical rite, and the study of the Eucharistic theology in the seventh-century manuscript, the Antiphonary of Bangor, could yield significant information to this debate. This paper will briefly outline the controversy regarding the early Irish Eucharistic rite, list the liturgical pieces related to the Eucharist in the Antiphonary of Bangor, and will focus on the theology behind supposedly the earliest Latin Eucharistic hymn, which is contained in this manuscript, plus its Eucharistic antiphons.