The _Requiem_, which Mozart composed for the most part while _Zauberflöte_ was ‘running,’ is the only ecclesiastical work which does not follow in the rut of his contemporaries. All his masses, offertories, oratorios, etc., are ‘unscrupulous adaptations of the operatic style to church music.’ The _Requiem_, completed by his pupil, Süssmayr, according to the master’s direction, shows all the attributes of his genius--‘deeply felt melody, masterful development, and a breadth of conception which betrays the influence of Handel.’ ‘But,’ concludes Riemann, ‘a soft, radiant glow spreading over it all reminds us of Pergolesi.’ Yes, and that influence is felt in many a measure of this work--we should be tempted to use a trite metaphor if Pergolesi’s mantle were adequate for the stature of a Mozart. As perhaps the finest example, in smaller form, of his church music we may refer the reader to the celebrated _Ave verum_, composed in 1791, which is reprinted in our musical supplement. * * * * * Through Haydn and Mozart orchestral music emerged strong and well defined from a long period of dim growth. Their symphonies are, so to speak, the point of confluence of many streams of musical development, most of which, it may be remarked, had their source in Italy. The cultivation of solo melody, the development of harmony, largely by practice with the figured bass, until it became part of the structure of music, the perfection of the string instruments of the viol type and of the technique in playing and writing for them, the attempts to vivify operatic music by the use of various _timbres_, all these contributed to the establishment of orchestral music as an independent branch of the art. The question of form had been first solved in music for keyboard instruments or for small groups of instruments and was merely adapted to the orchestra. These lines of development we have traced in previous chapters. The building up of the frame, so to speak, of orchestral music was synthetical. It had to await the perfection of the various materials which were combined to make it. This was, as we have said, a long, slow process. The symphony was evolved, not created. So, in this respect, neither Haydn nor Mozart are creators. But once the various constituents had fallen into place, the perfected combination made clear, new and peculiar possibilities, to the cultivation of which Haydn and Mozart contributed enormously. These peculiar possibilities were in the direction of sonority and tone color. In search of these Haydn and Mozart originated the _orchestral_ style and pointed the way for all subsequent composers. In the Haydn symphonies orchestral music first rang even and clear; in those of Mozart it was first tinged with tone colors, so exquisite, indeed, that to-day, beside the brilliant works of Wagner and Strauss, the colors still glow unfaded.