Every Sunday, 9.15 am, from mid-September to June the Vienna Court Music Ensemble performs the Holy Mass at the Imperial Chapel. This continues a tradition going back more than 500 years, which began in the time of the Habsburg rulers. The Vienna Court Music Ensemble consists of the Vienna Boys Choir, members of the Vienna State Opera men’s choir and members of the Vienna State Opera Orchestra.
The ensemble’s repertoire covers sacred music from the Renaissance until today and focuses especially on the masses of Haydn, Mozart, Beethoven, Schubert and Bruckner. The changing parts of the Holy Mass are sung in plainchant by the "Choralschola der Wiener Hofburgkapelle" (Schola of the Vienna Hofburg Chapel), a group of former members of the Vienna Boys Choir.
At the end of the Holy Mass, the Vienna Boys Choir sings motets in front of the altar.