Hector Berlioz's „Messe solennelle“, which the composer claimed he destroyed, was rediscovered 150 years later completely by surprise in the organ loft of a church in Antwerpand sensationally premièred in the musical capitals of Europe by John Eliot Gardiner. Since then it has found widespread acceptance and been included in the repertoires of oratorio choirs everywhere. The tenth number, „O salutaris“, is ideally suited for performance in church services, and has been arranged for performance with chorus and organ. The Berlioz scholar and musician Hugh Macdonald has successfully transferred BerIioz's  colourful orchestral writing into a richly textured part for organ.<br>