Under Sarum usage Dum sacrum mysterium was the Antiphon to the Magnificat at Vespers on Michaelmas (Feast of Saint Michael and All Angels) which falls on September 29th. It was also used as the cantus firmus to Robert Carver’s Mass setting Missa Dum sacrum mysterium which was most probably used as the coronation Mass for king James IV of Scotland. It’s performed below by The Sixteen conducted by Harry Christophers. Enjoy :-).
Dum sacrum mysterium
Dum sacrum mysterium cerneret Johannes, archangelus Michael tuba
While John surveys the divine mystery,
Performers: The Sixteen conducted by Harry Christophers.