Samuel Barber Agnus Dei (3 versions), School for Scandal

When people far in the future are choosing a short list of sacred music from our time, Agnus Dei by Samuel Barber will probably be up there along with the music of Bach and Mozart.  Agnus Dei began as the second movement of Barber's String Quartet in B Minor (1937) and Toscannini asked for it to be arranged for orchestra where it became the Adagio for Strings (1938). Later Barber set it to part of a mass and named the resulting choral version Agnus Dei (1967).   

On this playlist the SQ is by the Emerson SQ, the Adagio for Strings by Shippers and the Agnus Dei by the Choir of Trinity College. This playlist also includes Barber's wonderful piece, Overture to the School for Scandal, which he wrote as his first orchestral composition while a student at the Curtis Institute of Music. (Must have been tough on the faculty.)

The album with Agnus Dei is a 2 CD's collection of of Barber's work and includes a well regarded (and slower) version of Adagio for strings by Bernstein and also the curious piece Knoxville Summer of 1915.