Final answer:
Richard Wagner considered himself the true successor of Beethoven, contributing significantly to opera with progressive ideas and innovations like the orchestral pit.
Step-by-step explanation:
Richard Wagner saw himself as the true successor of Beethoven. Wagner was among the progressive composers like Berlioz and Strauss, known for challenging the conventional boundaries of music during their times. Though the information provided discusses various historical figures, Wagner's innovations in opera and his self-view regarding his place in the legacy of classical music are clear from his actions and the development of his theatrical concepts, such as the orchestral pit to better immerse audiences into the performances.