The singing style of playing was further developed by the immortal Wolfgang Amadeus Mozart (1756-1791). The instrument on which he played was the harpsichord, and the evenness of its tone encouraged his natural predilection for a vocal style. Mozart was a master of writing for singers, as is shown by his operas, and he readily saw his way to preserving the vocal manner in his playing of the harpsichord and his compositions for it. He held that a good pianist should have a perfect legato style (legato means "bound," and legato style is that in which the notes flow smoothly one into the other) a singing touch and a manner without affectation. Mozart did not live long enough to benefit much from the growing acquaintance with the newly invented piano, but one of his contemporaries, who outlived him by more than two-score years did so. This was Muzio Clementi (1752-1832), a man of no genius in composition, but of exceptional capacity for the reception of suggestions from his instrument. Clementi's mind appears to have been largely occupied with the problem of the possibilities of the piano. Yet he was not wholly devoted to the development of power and rapidity, for after a memorable meeting with Mozart he cultivated the singing style more assiduously than he had previously. He lived through a period of vital growth in music, for he was a contemporary of Haydn, Mozart, Weber and Beethoven. It would have been strange had he been insensible to the productions of such an era. In his youth, and indeed through most of his life he lived in England, and there he formed his early style on the English piano, which had thick strings, a heavy touch and a deep hammer fall. The result was that his music abounded in bold and brilliant passages of octaves, thirds, and sixths. He aimed at a sonorous and imposing musical diction, and he demanded of a pianist great physical power. Clementi's piano technic was the first which was clearly differentiated from that of the harpsichord and his "Gradus ad Parnassum" (1817) a series of 100 studies, remains to this day the foundation of solid piano playing. Many things have since been added to piano technic, but Clementi's rules lie at the base of it.