Which composer wrote the Ride of the Valkyries?

Wagner, from Die Walkure, the second opera of a four-part cycle that runs about fifteen hours and took him twenty-six years to write. He built his own theatre at Bayreuth to stage it, with the orchestra hidden in a covered pit and the auditorium darkened - both innovations, and both now standard practice everywhere.

The technique that made him matter is the leitmotif: short musical ideas attached to characters, objects and ideas, which recur, combine and transform as the drama moves - so the orchestra can tell you what a character is thinking while they say something else, or foreshadow an event by quoting its theme before it happens. Every film score since owes him that, and John Williams's Star Wars music is a direct and acknowledged application of it.

He was also a virulent antisemite who published an essay on Jewishness in music, and Hitler adored him. Whether the operas themselves are antisemitic is genuinely argued, including by Jewish conductors and scholars who love the music; his works were informally unperformed in Israel for decades, and attempts to break that have caused walkouts and shouting in the hall. It is one of the hardest cases in art of what to do when the work is essential and the man was appalling.