The nineteenth century was the golden age of the great virtuoso pianists who were required by the tradition of the day to compose music to perform at their own concerts. During the earlier part of the century in particular, much music was written primarily as a vehicle to display the virtuosity of the performer, and contained every conceivable technical difficulty. Vast numbers of fantasies, rondos and sets of variations on the popular tunes of the day appeared, which were the subject of much adverse criticism from serious musicians and composers, represented in particular by Robert Schumann. However, by the second half of the century, public taste and opinion was changing, and there was now more emphasis on original creative ability rather than on mere bravura display for its own sake.