Carl August Nicholas Rosa (Karl August Nikolaus Rose) was a German violinist and conductor born on March 22, 1842 (Brahms was 9 years old.) He began his career as a violin prodigy, having studied in Leipzig and Paris. In 1863, he was concertmaster of some orchestra in Hamburg though I don’t know which orchestra. He began his conducting career while in Hamburg. From 1869 to 1872, he toured the U.S. with an opera company he formed with a singer who became his wife sometime during the tour. The operas they staged were sung in English. In 1873, he and his wife started the Carl Rosa Opera Company in England, which survives to this day. None other than Gustav Holst played (first trombone) in this company's orchestra for a while. Another man who played in the orchestra was (violinist) Marie Hall's father. (After Rosa's death, the company introduced opera to the masses by offering reduced prices for an entire season.) Rosa died suddenly on April 30, 1889 at age 47.