At the heart of virtually all the medieval music that survives, is the human voice. This is an ancient heritage. The early Christians under the Roman Empire believed themselves to be engaged in a pilgrimage through a transitory world, where they were strangers, to their true home and an eternal liturgy ‘where my servants shall sing for joy of heart’, as St John the Divine says in Revelation. But why have singing in worship? What was to be gained, in the early Church and in its medieval descendant, by having a choir singing snippets of the Scripture, often extracted from their original context and sewn together in new patterns? We shall find that the answer lies in the breathing body.