"Dearest Pleyel,

The bearer of this letter is one of my pupils in composition, by the name of Haensel, a charming young man of the best character, and also a good violin player. He has asked me to introduce him to you, so that if necessary you can lend him a helping hand. You will see how talented he is by examining his three new Quartets. He is in the service of the Polish Princess Lubomirsky, and for that reason I suggest that you treat him kindly..." 

Haydn wrote this introduction in December of 1802 to his student Ignaz Pleyel, on behalf of Peter Hänsel, who carried it to Paris where Pleyel had been publishing Haydn's quartets. In the 1790's Pleyel and Haydn were both in London, set up by rival concert promoters as enemies on stage, but nevertheless they remained loyal friends and colleagues, attending each other's concerts and dining together. Now Pleyel was engaged in the first "collected" edition of Haydn's quartets in parts. Haydn was grateful to his former pupil for this effort, prophesying that "because of their beautiful engraving, the paper—and the fact that they are so correct—as well as their general appearance, you will be remembered for them forever." And Haydn was correct. Because his sources were sometimes far from Haydn's originals, Pleyel's somewhat arbitrary groupings and numberings (judged by current standards) have required generations of scholarship to straighten out. But they remain the standard identifiers of the quartets to this day. 

In Haydn's letter on behalf of Hänsel we see 18th century networking in action. The Polish Princess Izabella Lubomirska (1736–1816) was an influential, free-thinking, and free-spending patroness of the arts in Vienna. She had caught the eye of Casanova and of Goethe, and Hänsel himself referred to her as “unforgettable”. It seems in character for Haydn to recommend to Pleyel that he make himself useful to Hänsel not only on his own recommendation, but for the connection it would afford Pleyel to the Princess. It was not what you knew but whom you knew, in sæcula sæculorum. 

Peter Hänsel (1770–1831) wrote almost exclusively chamber music, tailored to the musicians in the employ of his Princess, a keyboard player, and her son, a harpist. His 58 string quartets seem to have his own playing in mind as the first violinist. As another example of networking, the set of three published at the beginning of 1799 as his Opus 5 were dedicated “to Mr. Joseph Haydn, to show his keen gratitude, by his devoted Servant and Pupil Pierre Hänsel”. With this work, and Mozart’s Dissonant Quartet, we close for now our survey of quartets dedicated to Haydn during his lifetime.