for SATB (with divisions) unaccompanied Characteristically sung on Christmas Day, this Catholic chant depicts mystery and wonder at the birth of Jesus, as witnessed by the animals. The second half of the text relates to words spoken by Elizabeth, welcoming Mary into her home. In McDowall's setting, deep, sonorous chords open and close the piece, which has a sustained tempo that gives space for the melismatic vocal lines and rich harmonies to take full effect. O magnum mysterium is the first of McDowall's set of three 'O' text settings conceived as Trinity Triptych.