Wagner was the literary musician par excellence. He could not, like Mozart and Beethoven, produce decorative tone structures independently of any dramatic or poetic subject matter, because, that craft being no longer necessary for his purpose, he did not cultivate it. As Shakespeare, compared with Tennyson, appears to have an exclusively dramatic talent, so exactly does Wagner compared with Mendelssohn. On the other hand, he had not to go to third rate literary hacks for "librettos" to set to music: he produced his own dramatic poems, thus giving dramatic integrity to opera, and making symphony articulate. A Beethoven symphony (except the articulate part of the ninth) expresses noble feeling, but not thought: it has moods, but no ideas. Wagner added thought and produced the music drama. Mozart's loftiest opera, his Ring, so to speak, The Magic Flute, has a libretto which, though none the worse for seeming, like The Rhine Gold, the merest Christmas tomfoolery to shallow spectators, is the product of a talent immeasurably inferior to Mozart's own. The libretto of Don Giovanni is coarse and trivial: its transfiguration by Mozart's music may be a marvel; but nobody will venture to contend that such transfigurations, however seductive, can be as satisfactory as tone poetry or drama in which the musician and the poet are at the same level. Here, then, we have the simple secret of Wagner's preemminence as a dramatic musician. He wrote the poems as well as composed the music of his "stage festival plays," as he called them.