This past Thursday, in a piece for Examiner.com about the first symphony of Gustav Mahler, I presented the extensively prolonged introduction to the first movement in terms that the German Medievalist Ernst Robert Curtius had applied to the Roman poet Ovid. Curtius was discussing the literary genre of landscape description, and he was specifically comparing Ovid to Virgil. His point was that Virgil approached description as a process of composition presenting the component parts and elaborating on how they were assembled in what Curtius called an "epic succession of scenes." Ovid's approach, on the other hand, involved a strong preference for rhetoric over logic, using rhetorical devices to convey the impression that the described landscape "comes into existence before our eyes." In my Examiner.com piece I referred to Ovid's strategy as one of disclosure to distinguish it from Virgil's "composition."
On further reflection I realize that one possible indicator of "progress" in music history may involve an appreciation of rhetoric-based disclosure as an alternative to logic-based description. We find approaches to "sound painting" through music going all the way back to the Middle Ages; and in its earliest forms it tends to be based on the "composition" of sound effects. Tonight in San Francisco San Francisco Renaissance Voices will be singing examples of this approach in the Festino nella sera del giovedì grasso ("Entertainment for the eve of Carnival Thursday") of the Renaissance composer Adriano Banchieri. More familiar to most listeners is Antonio Vivaldi's musical "translation" of four descriptive sonnets, one for each of the four seasons of the year, in the first four of his Opus 8 violin concertos. We find a similar compositional approach to description in the sixth ("Pastoral") symphony of Ludwig van Beethoven.
Without trying to be historically accurate over when the disclosure strategy first appeared in music, I would suggest that its first major appearance took place in the prelude to Richard Wagner's Das Rheingold, where, with his customary arrogance, he brought "into existence before our eyes" (or ears) the entirety of the natural world. I selected Wagner because, as a conductor, Mahler was as familiar with Wagner as he was with Beethoven. Thus, he understood that certain works were of a descriptive nature (what we would call a "text type" in literary theory) and that Wagner had pursued a descriptive strategy significantly different from that of Beethoven. Thus, it may be that he decided to take Beethoven's approach in composing his Wayfarer songs and then move on to Wagner's strategy to begin his first full symphony, which drew upon material from that song cycle.