O du eselhafter Peierl

"O du eselhafter Peierl", K. 559a, is a canon composed by Wolfgang Amadeus Mozart. The music, originally in F major, is set for four singers. The words are probably by Mozart himself.
Origin.
The work was written sometime between 1785 and 1787. On 2 September 1788, Mozart entered it into his personal catalog of works as part of a set of ten canons. Although some of the canons in the set of ten have serious (that is, religious) lyrics, K. 559a was meant for fun, a gesture of mocking, scatological humor directed at a friend of Mozart's, the baritone (1761–1800). The canon begins:<poem lang="de" style="float:left;">
O, du eselhafter Peierl
O, du peierlhafter Esel</poem>
<poem style="margin-left:2em; float:left;">Oh, you asinine Peierl
oh you Peierline ass.</poem>
Later, the lyrics include "O leck mich doch geschwind im Arsch" ("Oh lick me real quick in the ass (arse)"), a favorite expression in Mozart's scatological works. For more examples and discussion, see Mozart and scatology.
"O du eselhafter Peierl" was originally intended to be sung immediately following "Difficile lectu". For the tale of how these two canons originated, see "Difficile lectu".
Revised version.
Mozart later transposed "O du eselhafter Peierl" into G major, in versions that replaced "Peierl" with the names of two other individuals, named Martin and Jakob. There are other minor differences in words and notes.
According to Link (2007), "Martin" was the composer Vicente Martín y Soler. Mozart scholar Alfred Einstein suggested a different hypothesis, that "Martin" was Philipp Jakob Martin, who served as impresario for Mozart's concerts in the and in the Augarten. The lyrics of the revised canon replace "Nepomuk" (see above) with "Lipperl", a German diminutive form of "Philipp".
Autographs.
The autograph (original manuscript copy) of K. 559a has survived; it is a "tiny slip of paper" (Searle) on the reverse side of which is the original of K. 559. For discussion, see Difficile lectu. The later G major version, K. 560, is also preserved and is currently in the Mozarteum in Salzburg.
Reception.
The canon is perhaps the most often performed of Mozart's comic canons; performances have often used bowdlerized versions of the lyrics.
Zaslaw and Cowdury (1990) express admiration for the work, saying "it makes brilliant use of imitative and hocket-like devices" and "possesses the clockwork-like vocal interplay of a well-wrought "opera buffa" ensemble."