The medieval office of Corpus Christi
The feast of Corpus Christi was officially instituted for the whole Church by Urban IV on 8th September 1264. Urban IV had previously been archdeacon of Liège and confessor of Julienne de Cornillon who was, with Eve of Liège, the promoter of this festival. The composition of the texts for the office of Corpus Christi is attributed to Saint Thomas Aquinas, who was then in Paris. It was at this time that he also wrote his ‘Summa Theologica’, contemporary with the musical writings of another Dominican, Jerome of Moravia, who was also in Paris at the time. It can be legitimately assumed that, the music for this office was composed by Jerome of Moravia. In any case, the treatise of Jerome is the only text from the Middle Ages that describes the different ways of interpreting square notation. Thus, with this office, we have a precious testimony of music composed at the same time as the treatise that explains how to compose and perform this...