 The purely orchestral works fall into two categories.The best-known ones in the West, and perhaps the finest in overall quality, are mainly programmatic in nature—in other words, the musical content and how it is handled in the piece is determined by the plot or characters in a story, the action in a painting or events reported through another non-musical source.The second category of works are more academic, such as his First and Third Symphonies and his Sinfonietta.