Baron Hans Guido von Bülow (January 8, 1830February 12, 1894) was a German conductor, virtuoso pianist, and composer of the Romantic era. One of the most famous conductors of the 19th century, his activity was critical for establishing the successes of several major composers of the time, especially Richard Wagner and Johannes Brahms. Along with Carl Tausig, Bülow was perhaps the most prominent of the early students of Hungarian virtuoso pianist, conductor and composer Franz Liszt. He became acquainted with and eventually married Liszt's daughter Cosima, who later left him for Wagner. Noted for his interpretation of the works of Ludwig van Beethoven, he was one of the earliest European musicians to tour the United States.