Anton Stadler (1753 - 1812) was a clarinet and basset horn player for whom Wolfgang Amadeus Mozart wrote both his Quintet_for_Clarinet_and_Strings and Clarinet Concerto. He was reputed to have a beautiful tone, with exceptional mastery of the low register of the clarinet and basset horn playing. A noted virtuoso, he played second to his brother Johann in the Vienna Court Orchestra. It was possibly this specialism in second clarinet along with the basset horn that led to his collaboration with Theodore Lotz, a clarinet maker. His idea was to add an extension to his Bb and A clarinets in the same vein as the basset horn- an extra major third to a low c. It was for this extended clarinet (now known as the basset clarinet but initially called a bass-clarinet in the days before the modern bass had been invented) that the Clarinet Concerto and possibly the Quintet_for_Clarinet_and_Strings were written. 1753 was a common year starting on Monday (see link for calendar). ... 1812 was a leap year starting on Wednesday (see link for calendar). ... A bass clarinet, which sounds an octave lower than the more common Bâ™­ soprano clarinet. ... Basset-horn The basset-horn is a musical instrument, a member of the clarinet family. ... W. A. Mozart, 1790 portrait by Johann Georg Edlinger Wolfgang Amadeus Mozart (January 27, 1756 – December 5, 1791) is among the most significant and popular composers of European classical music. ... Quintet for Clarinet and Strings in A (also called Clarinet Quintet in A Major) is the common name of the Mozart composition with the Köchel number of 581. ... Mozarts Clarinet Concerto in A major, K. 622 was written in 1791 for the clarinettist Anton Stadler. ... A virtuoso (from the Latin virtus meaning: skill, manliness, excellence) is an individual who possesses outstanding mechanical ability at operating a musical instrument. ... Mozarts Clarinet Concerto in A major, K. 622 was written in 1791 for the clarinettist Anton Stadler. ... Quintet for Clarinet and Strings in A (also called Clarinet Quintet in A Major) is the common name of the Mozart composition with the Köchel number of 581. ...

There have always been rumors that Stadler's friendship with fellow Mason Wolfgang Amadeus Mozart was inspired by greed; pawning works written for him, borrowing sums of money that he never repaid and constantly eating and drinking at Mozart's expense. However these are still rumours, and have never been conclusively substantiated.