The end of the extraordinary life of the baroque sonata was marked by the beginning of a significant transformation: the predominance of stringed instruments (particularly the violin) gave way to a gradual affirmation of the keyboard, emancipated from the function of basso continuo in order to take on the role of soloist. The musicians who gave birth to the style galant and the Rococo provided countless examples of sonatas for the keyboard “accompanied” by the violin or flute, often together with the cello, an obvious remnant of the trio sonata. This “accompaniment”—entrusted to instruments that we would today think of as soloists, themselves accompanied in turn by the piano—usually consists of held notes or doublings of a part already played by the keyboard. It normally presents little or no technical demands, and in fact may be played by an amateur. And since it does not alter the structure of the piece in any way but in timbre, it is often indicated as “ad libitum”. Clementi undoubtedly played an important role in the evolution of the sonata, and his catalogue includes works for keyboard with an accompaniment like that just described (op. 13 and 31 with violin or flute, op. 21, 22, 29 and 32 with the addition of the cello). The 3 sonatas of op. 15 “for the piano with an obbligato accompaniment on the violin”, however, deserves a separate discussion. Published in London in 1786 and recently republished by Ut Orpheus as part of Clementi’s complete works, these pieces feature a well-developed discourse between the two instruments, with the violin and piano functioning as equal partners in the dialogue.