The invention which overthrew the clavichord and the harpsichord and brought into existence the piano was the hammer action. For years the problem of applying the keyboard to the principle of the dulcimer, already explained, had occupied the minds of instrument builders. The solution was the work of Bartolomeo Cristofori, born at Padua, May 4, 1653, and it was made public in 1711. Two others claimed the honor: Gottfried Silbermann and Christopher G. Schröter. In 1726 Silbermann made two pianos and showed them to Bach, who condemned them because of their heavy touch and the weakness of their trebles. Silbermann was discouraged, but according to Agricola, a contemporary writer, he worked at improvements upon his instruments, and sold one of them to Frederick the Great, in whose music room it stood till 1880. It was then examined by Bechstein, the leading German piano maker of to-day, who found that it contained the Cristofori action. The priority of Cristofori's claims is established by an article written by Scipione Maffei and printed in the "Giornale dei Litterati d'Italia," in 1711, with a diagram of the inventor's hammer action. A translation of Maffei's article will be found in Rimbault's "The Pianoforte." (London, 1860.) It was also published in German in Matheson's "Musikalische Kritik," in Hamburg, 1725, so that the contemporaries of Silbermann and Schröter ought to have known of Cristofori's work. Indeed, Schröter's claim was made by himself in a letter written in 1738, which appears to have been evoked by irritation at Cristofori's glory. It should be noted here that in the letters of an instrument maker named Paliarino, written in 1598, the instrument "piano e forte" is twice mentioned. It has been conjectured, and probably rightly, that this was a harpsichord with contrivances for loud and soft effects, for it is unlikely that even a rude hammer action could have been in existence more than a century before Cristofori's invention. It is, however, probable that some attempts were made before his, for his was altogether too satisfactory to have been anything but the result of a development. Nevertheless it was the first hammer action of permanent value, and its essential principles are employed in the finest actions of to-day. Therefore Cristofori fairly deserves the honor of inventing the piano. The instrument, however, did not gain great favor in Italy, owing to the inability of the harpsichord players to acquire the right touch, and it soon fell into disuse. Silbermann, however, following the details of Maffei's letter before-mentioned, built pianos, and other German makers, notably Friederici of Gera, who is said to have made the first square piano, followed his lead. At least as early as 1766 Johannes Zumpe built square pianos in England.