Later, Mozart revealed his low opinion of Clementi:.

             "He is an excellent cembalo-player, but that is all. He has great facility with his right hand. His star passages are thirds. Apart from this, he has not a farthing"s worth of taste or feeling; he is a mere mechanicus" (Westrup 131).

             Clementi, on the other hand, had nothing but great things to say about Mozart. "Until then, I had never heard anyone play with such spirit and grace," he said (Bower 485). Clementi also personally knew Haydn and Beethoven, and survived both of them, as well as Mozart (Westrup 131). .

             Clementi eventually made his way back to London in 1782, where he accepted J. B. Cramer as his pupil. Among a full schedule of concerts, Clementi was a regular soloist for the Hanover Square Concerts. His busy career came to a quick hault when he left for France to elope with an eighteen-year-old. When the father of the girl put a stop to it, a disheartened Clementi retired to Berne until 1785. During this period, he wrote some of his most memorable pieces, including 26 new sonatas. Clementi returned to London in 1785, achieving fame as a composer, performer, teacher, publisher, and instrument manufacturer. As with most composers of the time, Clementi performed his own compositions in his concerts. His last known public concert was in 1790. Haydn, who was visiting England around this time, was becoming the prefered musician in London. Because of Haydn"s popularity, Clementi declined as a soloist, but was in great demand as a piano teacher. In fact, Clementi is even said to have refused the application for tuition from the royal family itself. He was also reported to have charged one guinea per lesson (Bower 485). Clementi invested his considerable earnings in piano manufacturing (Arnold 420). After the musical instrument and publishing house he became interested in failed (Wier 349), Clementi established a firm for piano-making, as well as music publishing, in 1798 (Sadie 171).