The early Classical period was ushered in by the Mannheim School, which included such composers as Johann Stamitz, Franz Xaver Richter, Carl Stamitz, and Christian Cannabich. It exerted a profound influence on Joseph Haydn and, through him, on all subsequent European music. Wolfgang Amadeus Mozart was the central figure of the Classical period, and his phenomenal and varied output in all genres defines our perception of the period. Ludwig van Beethoven and Franz Schubert were transitional composers, leading into the Romantic period, with their expansion of existing genres, forms, and even functions of music.