literally(with a double bar and sign of repeat); later, as com-
posers gained freedom, with considerable amplification. Each
half presented thesamematerial (it was aone-theme form) but
the two halves were contrasted intonality,i.e., the first part, be-
ginning in the home-key, would modulate to some related key—
generally the dominant; the second part, starting out in this
key, gradually modulated back to a final cadence in the original
key, and often—especially in Haydn and Mozart—repeated the
entire main sentence of the first part. The general effect of such
a form has been wittily described[65] as resembling the actions
of “the King of France who, with twenty thousand men, marched
up the hill and then marched down again”—but he surely had
no exciting adventures in between! It is evident that this form,
while favorable to coherence and unity, is lacking in scope and
in opportunity for variety and contrast. It did, however, em-
phasize the principle of recapitulation; in fact it became the
convention (as we shall see in the dances of the Suite) for the
closing measures of the second part to be an exact duplicate in
the home-key of that which had been presented at the end of
part one. We shall observe, as we continue our studies, that
the trend of musical composition gradually swung over to the
Three-part form, the essential feature of which is restatement
afterintervening contrast.
[Footnote 65: SeeThe Appreciation of Musicby Surette and
Mason, p. 36.]
For illustrations of the Two-part Form see the Supplement Nos.
20, 21, 22, 23, 24.
Only in such comparatively simple examples as those just cited
is found this perfect balance in the length of the two parts. We
often observe extended sentences in the first part; and it became
the custom for the second part to be considerably lengthened, to
include modulations into more remote keys and even to display
certain developments of the main material. For a striking exam-
ple of a movement which, although definitely in Two-part form,
(i.e., it is in two clear divisions and has butonetheme) is yet of
considerable scope and variety, see the Allegretto of Beethoven’s
Fourth Sonata. It was, in fact, this instinct for contrasting vari-
ety in the second part[66] which (as can be shown from historical
examples)[67] gradually led to the developing and establishment
of the Three-part form.