Piano Sonata in C major, Hob. XVI/50
by Joseph Haydn
I. Allegro 
II. Adagio
III. Allegro Molto

In 16th May, 1795, Haydn witnessed the marriage of Therese Jansen and Gaetano Bartolozzi. at Saint James Church, Piccadilly, London. Other witnesses include Charlotte Jansen, Gaetano's father, Francessco Bartolozzi, the famous engraver, Maria Adelaide de la Heras.

This was the second visit of Haydn to London, a then well-known composer of Austrian. Before that, in 4th May, Haydn had hold a benefit concert in London to much success. The programme includes: Symphony no. 104, nicknamed "London Symphony"; Cantata "Scena di Berenice" for Brigida Giorgi Banti, a work which latter being used as a model for Beethoven's own work. In fact, both visits to London had brought great success and financial benefits to Haydn.

Haydn most probably had been fiddling with some English pianos (namely Broadwood/Longman/Broderip, which is generally larger, louder, more robustly constructed, and boasting wider range of notes; compare with then Austrian fortepianos, namely Walter/Schanzt), and befriended with some good pianists or musicians there, as Therese Jansen is likely one of them. Therese Jansen was an uprising pianist in the then London scene, a famous students of well-known pianist, Muzio Clementi. With her secured technique on the piano, probably rather virtousic, these probably had inspired Haydn to "composed expressively" for her some "grand concert sonatas", a subgenre of piano sonata that Haydn had never attempted before. Hence, Haydn had dedicated the last three of his piano sonata to Therese Jansen (Hob. 50 - 52), and subsequently composed another three piano trios for her.

Therese Jansen's bravura on the piano can be seen in these three sonata, as these works boast abundance of technical and musical demands from the player: fast running notes; quick turns; or double-thirds turns and passage; tonality contrasts, etc.

Hob. 50 is in C major, for both outer movements; and adopted a more serene F major for the middle movement. The fast movements boasting lavishly of musical humours, and intriguing tonal progression. These features make this piece a favourite among pianists' programme until nowadays.

In this sonata, the first movement is in sonata form and the longest. Instead of starting the piece with grand chords in arpeggiations (a cliche most composers adopted at that time for the genre of 'grand sonatas'), it starts the main theme with a quiter, simple broken chord. This opening theme, though harmonically stays put in tonic chord, the melody runs rather freely, eschewing the dissonance it creates against the harmony; seems already in the mood of pushing the envelope of then 'musical rules'. The theme end with a prolonged appoggiatura, also a rather unusual musical gesture, then it succumbs into 'grand' chords, which is a standard expectation in 'grand sonata' genre. Then music is then continued running wild, throwing much technical challenges to the player: quick running passage, double-thirds turns, etc.

Through out this whole movement, the same opening theme would be kept re-emerging. In fact the whole movement almost seem being proliferated with this single theme. But the music is kept interesting with the theme being be put through adventurous harmonic progression, further developed, and varied, and modulated to much remote keys.

The second movement is in F major, ternary form. It can roughly divide into three parts. The outer parts bear the same theme, which the second time with some variation. The middle part is in minor key, and contrapuntal in feature. This expressive movement gives a rather calm and thoughtful experience.

The third movement is more lighthearted and scherzando (playfully) in feature, also in ternary form. Most of the melody is in bouncy staccatissimo, with some abrupt halt, perhaps suggest a game between silence and sound (a much reminder of Haydn's 'Surprise Symphony').

Overall, this sonata offers a pleasant ride for both the listener and performer, with its sunny disposition and abandon of musical wit which never fails to tickle.