title: The Blue Danube
context: "The Blue Danube" is the common English title of "An der schönen blauen Donau", Op.314 (German for "By the Beautiful Blue Danube"), a waltz by the Austrian composer Johann Strauss II, composed in 1866. Originally performed on 15 February 1867[1][2] at a concert of the Wiener Männergesangsverein (Vienna Men's Choral Association),[2] it has been one of the most consistently popular pieces of music in the classical repertoire. Its initial performance was considered only a mild success,[1] however, and Strauss is reputed to have said, "The devil take the waltz, my only regret is for the coda—I wish that had been a success!"[2]
question: When did Strauss write his Danube Waltz?
answers.text: 1866 1866