How did the coming to power by Europe's middle classes affect the arts, literature, and music during this period? Using particular examples,...

During the Romantic Era, the rise of the middle class in Europe had an important impact on the arts, literature, and music of the day.

With regard to music, prior to this era, music had been performed for elite, well-educated audiences who were something of music connosieurs.  With the rise of the middle class, music had to be aimed at people who were not so knowledgable.  At this point music became more like today's music -- aimed at the masses.

The same sorts of things happened to art and literature.  In the Romantic Era these came to be more accessible to the masses and more democratic in nature.

Overall, then, the rise of the middle class in the Romantic Era led to arts that were aimed at that middle class and were therefore less of what we might now call "high-brow."