Wolfgang Amadeus Mozart composed his Clarinet Concerto in A major, K. 622, in 1791. It was written for clarinetist Anton Stadler, and it was among the latest works Mozart completed, and his final purely instrumental work (he died in the December following its completion). The concerto is notable for its delicate interplay between soloist and orchestra, and for the lack of overly extroverted display on the part of the soloist. As no autograph survives and as it was published posthumously, it is difficult to understand all of Mozart's intentions: the only relic of this concerto written in Mozart's hand is an excerpt of an earlier rendition written for basset horn in G. Most likely Mozart originally intended the piece to be written for basset horn, but eventually was convinced the piece would be more effective for clarinet. However, since several notes throughout the piece go beyond the conventional range of the A clarinet, we can presume it was intended to be played on the basset clarinet, a special clarinet championed by Stadler that had a range down to low written C. Even in Mozart's day, the basset clarinet was a rare, custom made instrument, so when the piece was published, a new version was arranged with the low notes transposed to regular range. This has proven a problematic decision, as the autograph is lost, having been pawned by Stadler, and until the mid 20th century musicologists did not know that the only version of the concerto written by Mozart's hand had not been heard since Stadler's lifetime. The concerto was premiered in Prague in 1791 to a positive reception. The work calls for a solo clarinet in A, flute I/II, bassoon I/II, horn I/II (in A and D, often transcribed for horn in F), violin I/II, viola, cello, and double bass.
