Apparently the Middle Ages did not produce much music criticism. It could scarcely be otherwise if, as has been claimed, criticism as an institution, meaning ‘a specific discursive medium characterized by the controlled exercise of authority and judgment’ has ‘a history reaching back to the eighteenth century’ and seemingly no further. Consider the substantial repertoire of Gregorian chant, once employed throughout much of the Latin West, and the plainsong that is principally evoked in the title of this chapter. The monks, friars, nuns and clerics who sang this music in the liturgy were not required to perform in any sense of the word recognisable from many later periods of musical history, even when they were cantors assigned solo chants. Those standing near them in the choirstalls heard them sing, but we may suppose that they did not exactly listen for much of the time; plainsong was not designed to promote concentration upon an art of autonomous musical sound. Even if the music of a particular chant drew the ear of someone present, it was surely difficult to bring a varied discernment to bear upon material for which a pope, inspired by the Holy Spirit, was believed to be responsible.