In the Middle Ages, it was a very common custom to embellish the original texts of the liturgy with additions known as tropes. The most popular of these were the ones added to the Kyrie; the Mass Ordinaries in the Liber Usualis are still to this day named after them, as for example Kyrie fons bonitatis. When the tropes were used, the choir would sing the first Kyrie as follows: “Kyrie, fons
↧
