Hans Guido Freiherr von Bülow was a German conductor, virtuoso pianist, and composer of the Romantic era. As one of the most distinguished 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. Alongside Carl Tausig, Bülow was perhaps the most prominent of the early students of the Hungarian composer, virtuoso pianist and conductor Franz Liszt; he gave the first public performance of Liszt's Sonata in B minor in 1857. He became acquainted with, fell in love 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.