Doubt Quotes - page 75
By the late eighteenth century, there is a sad and permanent decline in the quality of music written for young performers or beginners: one has only to compare Bach's Album for Anna Magdalena Bach and the Two-Part Inventions with anything that came later. No composer of importance between Bach and Schumann turned his hand to writing for children, and Schumann's essays came after his years of greatest inspiration for piano writing had gone. (Mozart is the odd exception, but then he was, in fact, almost incapable of writing really easy pieces: he no doubt believed that his Sonata in D Major, K.576, was easy, perhaps because all the hard passages in the first movement were in simple two-part counterpoint, one voice in each hand, but he was wrong.)
Charles Rosen