For all we know Wolfgang Amadeus Mozart composed the Missa brevis K. 275 (272 b) in 1777 before going on an extensive concert tour with his mother, taking him as far as Paris in March 1778. He learned of the first performance of the mass shortly before Christmas 1777 by a letter from his father who praises the “peerless” singing technique of the castrato Francesco Ceccarelli. Mozart particularly cherished this mass setting, as repeated requests to send him the work for performance can be gathere...