Now, of earlier history, we do know that Hans Leo. von Hasler, said to have been born at Nuremberg in 1564, studied first with his father, but afterwards at Venice, and for a whole year under A. Gabrieli. Italian and German art are thus intimately connected; but what each gave to, or received from, the other with regard to the sonata seems impossible to determine. The Becker sonatas appeared at Hamburg, and surely E. Bach must have been acquainted with them. Becker in his preface mentions another Hamburg musician--a certain Johann Schop--who did much for the cause of instrumental music. Schop, it appears, published concertos for various instruments already in the year 1644. And there was still another work of importance published at Amsterdam, very early in the eighteenth century, by the famous violinist and composer G. Torelli, which must have been known to E. Bach. It is entitled "Six Sonates ou Concerts a 4, 5, e 6 Parties," and of these, five have three movements (Allegro, Adagio, and Allegro). Corelli was the founder of a school of violin composers, of which Geminiani,[4] Locatelli,[5] Veracini,[6] and Tartini[7] were the most distinguished representatives; the first two were actually pupils of the master. In the sonatas of these men there is an advance in two directions: sonata-form[8] is in process of evolution from binary form, _i.e._ the second half of the first section is filled with subject-matter of more definite character; the bars of modulation and development are growing in number and importance; and the principal theme appears as the commencement of a recapitulation. We should like to say that _binary_ is changing into _ternary_ form; unfortunately, however, the latter term is used for a different kind of movement. To speak of a movement in sonata-form, containing three sections (exposition, development, and recapitulation) as in binary form, seems a decided misnomer. The violinists just mentioned were the last great writers of sonatas in Italy. Emanuel Bach arose during the first half of the eighteenth century, and, henceforth, Germany took the lead; Bach was followed by Haydn, Mozart, and Beethoven. The influence of the Corelli[9] school was felt in Germany and also in England. Sonatas were published by Veracini at Dresden in 1721, and by Tartini and Locatelli at Amsterdam before 1740. Again Veracini was for a time solo violinist to the Elector of Dresden (1720-23); Tartini lived for three years at Prague (1723-26), while Locatelli, during the first half of the eighteenth century, made frequent journeys throughout Germany. Emanuel Bach, the real founder of the modern pianoforte sonata, must have been influenced by their works. In a history of the development of the sonata generally, those of Corelli would occupy an important place, for in them we find not only fugal and dance forms, but also hints of sonata-form.