The classic orchestral composers are those who wrote the classic piano sonatas, and they developed their orchestral works on the same lines as those of their piano works. The symphony, as I have already said, is nothing more nor less than a sonata for orchestra; but it has its special characteristics, and these deserve some attention. The word "symphony" was first applied to separate instrumental portions of operas. For instance, an extended introduction to an aria was called "sinfonia." As ballet movements were introduced into operas, and instrumental preludes came to be employed, these separate pieces were more and more extended, and the term "sinfonia" came to be of considerable significance. The early composers were compelled to seek for some coherent design for their symphonies and as that played before the opera was the most independent of all, it was that in which a definite form first made its appearance. It was at first called "Sinfonia avanti l'Opera"--"symphony before the opera." As such it was written by Alessandro Scarlatti (1659-1725), and the French composer, Giovanni Battista Lulli (1633-1687). Lulli's overtures, as they came to be called, were divided into three movements, slow, lively, and slow, without pauses between them. A diametrically opposite form to this came to be known as the "Italian Overture." Its movements were lively, slow, lively--like those of the three-movement sonata--except that there was no pause between movements. The origin of this form is the same as that of the alternating movements of the sonata. It took firm hold as soon as it appeared, and from the beginning of the eighteenth century was the acknowledged form.