The six quartets:
1. String Quartet No. 14 in G major, ("Spring"), K. 387, Op. 10, No. 1 (31 December 1782)
2. String Quartet No. 15 in D minor, K. 421/417b, Op. 10, No. 2 (17 June 1783)
3. String Quartet No. 16 in E-flat major, K. 428/421b, Op. 10, No. 4 (June–July 1783)
4. String Quartet No. 17 in B-flat major ("Hunt"), K. 458, Op. 10, No. 3 (9 November 1784)
5. String Quartet No. 18 in A major, K. 464, Op. 10, No. 5 (10 January 1785)
6. String Quartet No. 19 in C major ("Dissonance"), K. 465, Op. 10, No. 6 (14 January 1785)
The quartets were published in a set (labelled Mozart's "Op. 10") in Vienna, 1785. Dates of completion are shown in parentheses above. Mozart arranged the six quartets in the order of composition, except for reversing the order of K. 428 and K. 458.
Wolfgang Amadeus Mozart composed 23 string quartets. The six "Haydn" Quartets were written in Vienna during the years 1782 to 1785. They are dedicated to the composer Joseph Haydn, who is considered the creator of the modern string quartet. Haydn had recently completed his influential "Opus 33" set of quartets in 1781, the year that Mozart arrived in Vienna. Mozart studied Haydn's string quartets and began composing this set of six, which were published in 1785. During this time, Haydn and Mozart had become friends, and sometimes played quartets together in Mozart's apartment, with Mozart playing the viola, and Haydn playing violin; see Haydn and Mozart.
Haydn first heard the quartets at two gatherings at Mozart's home, 15 January and 12 February 1785 (on these occasions he apparently just listened, rather than playing a part himself). After hearing them all, Haydn made a now-famous remark to Mozart's father Leopold, who was visiting from Salzburg: "Before God, and as an honest man, I tell you that your son is the greatest composer known to me either in person or by name. He has taste, and, what is more, the most profound knowledge of composition.
