<P> However, the forces destined to end the hold of the Classical style gathered strength in the works of many of the above composers, particularly Beethoven . The most commonly cited one is harmonic innovation . Also important is the increasing focus on having a continuous and rhythmically uniform accompanying figuration: Beethoven's Moonlight Sonata was the model for hundreds of later pieces--where the shifting movement of a rhythmic figure provides much of the drama and interest of the work, while a melody drifts above it . Greater knowledge of works, greater instrumental expertise, increasing variety of instruments, the growth of concert societies, and the unstoppable domination of the increasingly more powerful piano (which was given a bolder, louder tone by technological developments such as the use of steel strings, heavy cast - iron frames and sympathetically vibrating strings) all created a huge audience for sophisticated music . All of these trends contributed to the shift to the "Romantic" style . </P> <P> Drawing the line between these two styles is very difficult: some sections of Mozart's later works, taken alone, are indistinguishable in harmony and orchestration from music written 80 years later--and some composers continued to write in normative Classical styles into the early 20th century . Even before Beethoven's death, composers such as Louis Spohr were self - described Romantics, incorporating, for example, more extravagant chromaticism in their works (e.g., using chromatic harmonies in a piece's chord progression). Conversely, works such as Schubert's Symphony No. 5, written during the chronological dawn of the Romantic era, exhibit a deliberately anachronistic artistic paradigm, harking back to the compositional style of several decades before . </P> <P> However, Vienna's fall as the most important musical center for orchestral composition during the late 1820s, precipitated by the deaths of Beethoven and Schubert, marked the Classical style's final eclipse--and the end of its continuous organic development of one composer learning in close proximity to others . Franz Liszt and Frédéric Chopin visited Vienna when they were young, but they then moved on to other cities . Composers such as Carl Czerny, while deeply influenced by Beethoven, also searched for new ideas and new forms to contain the larger world of musical expression and performance in which they lived . </P> <P> Renewed interest in the formal balance and restraint of 18th century classical music led in the early 20th century to the development of so - called Neoclassical style, which numbered Stravinsky and Prokofiev among its proponents, at least at certain times in their careers . </P>

What city was considered the center for music during the classical period