Ludwig van Beethoven is one of the most influential figures in the history of classical music. Since his lifetime, when he was "universally accepted as the greatest living composer", Beethoven's music has remained among the most performed, discussed and reviewed in the Western world. Scholarly journals are devoted to analysis of his life and work. He has been the subject of numerous biographies and monographs, and his music was the driving force behind the development of Schenkerian analysis. He is widely considered among the most important composers, and along with Bach and Mozart, his music is the most frequently recorded. Beethoven expanded the formal and emotional scope – not to mention length – of nearly every genre in which he wrote. While he is most famous for his heightening of the symphonic form, Beethoven also had a dramatic influence on the piano sonata, violin sonata, string quartet and piano concerto, among several others. Only in the realm of vocal composition – opera and the mass – was his effect on later generations muted. Beethoven's stylistic innovations bridge the Classical and Romantic periods. The works of his early period brought the Classical form to its highest expressive level, expanding in formal, structural, and harmonic terms the musical idiom developed by predecessors such as Mozart and Haydn. The works of his middle period were more forward-looking, contributing to the musical language and thinking of the Romantic era, inspiring composers such as Franz Schubert, Felix Mendelssohn, Robert Schumann, Franz Liszt, Richard Wagner, and Johannes Brahms. His late period works were characterized by formal, harmonic, and structural experimentation at the highest level, often pointing toward contrapuntal tendencies and microscopic textures, as well as an increasingly introverted compositional outlook. Though rightly credited as a major harbinger of the Romantic era in music that followed, Beethoven never abandoned the fundamental formal paradigms and generally objective artistic philosophy characterizing musical Classicism to the same extent that later composers such as Berlioz or even Schubert did. Overview Beethoven's musical output has traditionally been divided into three periods, a classification that dates to the first years after the composer's death in 1827 and was formalised with the publication of Wilhelm von Lenz's influential work Beethoven et ses trois styles (Beethoven and his Three Styles). Lenz proposed that Beethoven's creative output be marked by three periods of distinct stylistic personality and he identified specific compositions as milestones for each period.