I think St Augustine was among the first in the West to write against a manner of singing in church that emphasized form rather than content. Though recognizing the merits of church singing, Augustine was wary of the pleasures of music stealing the thunder of devotion. This ambivalence towards liturgical music was to continue in subsequent centuries. There is a place for music in the liturgy, but words come first. At least in theory, because by the time of Chrodegang, bishop of Metz’ reform of the 9th century, these scruples seem to have disappeared. Music had become a form of devotion in itself.
In the first half of the 9th century, however, Agobard, bishop of Lyon, expressed reservations of a different kind. He wasn’t so much worried about intelligibility being held hostage to melismas, but that learning and scholarship were being sacrificed on the altar of liturgical singing. A new line of attack was opened. He wrote, and not very graciously:
“A great opportunity for being stupidly and harmfully employed is afforded to those young men and all generally whose duty it is to sing. Among their number there are many who from the beginning of childhood to white-haired old age spend all the days of their life learning and practicing song. They consume all the time they have for useful and spiritual studies –that is, reading and studying divine eloquence –engaged in this kind of thing.”
“Et adulescentulis atque omnibus generaliter, quibus cantandi officium iniunctum est, magna occasio stultae et noxiae occupationis aufertur. Ex quibus quam plurimi ab ineunte pueritia usque ad senectutis canitiem omnes dies vitae suae imparando et confirmando cantu expendunt, et totum tempus utilium et spiritalium studiorum, legendi videlicet de divina eloquia perscrutandi, in istiusmodi occupatione consumunt.”
Agobardi lugdunensis opera omnia, ed. L. Van Acker (Turnhout, 1981), 350, quoted in R.G. Witt, The Two Latin Cultures and the Foundation of Renaissance Humanism in Medieval Italy (Cambridge, 2012)
The next serious criticism against singing in church would come from Erasmus, but this time, it would be a question of style (polyphony), not principle. With Luther, however, singing would be enshrined in the life of the church and a new age of church music would be born.