Kuhnau, Becker is of immense importance. We are concerned with the
clavier sonata, otherwise we should certainly devote more space to
this composer. We have been able to trace back sonatas by German
composers to Becker (1668), and by Italian composers to Legrenzi
(1655); those of Gabrieli and Banchieri, as short pieces, not a group
of movements, are not taken into account. 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 à
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