It is nothing less than the great mystery of Christianity, of the incarnation of Christ that is described in O magnum mysterium. God’s only son became man and we encounter him as a baby in the manger. The motet of the Spanish composer Tomás Luis de Victoria is one of the most popular settings of this liturgical text. De Victoria succeeds in composing a heartfelt portrayal of the Nativity scene. His composition fascinates the listener through its clear forms and the poignancy of its musical expression.