What was the name of the period instrument ensemble that was formed in the 1950s by the conductor with whom Elisabeth Kulman recorded Beethoven's "Missa solemnis"?
Elisabeth Kulman:  She recorded Lieder by Mussorgsky, Bach's "Christmas Oratorio" with Peter Schreier and Beethoven's "Missa solemnis" with Nikolaus Harnoncourt. Nikolaus Harnoncourt:  Starting out as a classical cellist, he founded his own period instrument ensemble, Concentus Musicus Wien, in the 1950s, and became a pioneer of the Early Music movement.
Concentus Musicus Wien