claim: Wilhelm von Lenz, was a Baltic German Russian official and writer, and was a friend of many mid-century Romantic composers, including Hector Berlioz, that died on 8 March 1869, was a French Romantic composer, best known for his compositions "Symphonie fantastique" and "Grande messe des morts" (Requiem).
supporting_facts.key: Wilhelm von Lenz
supporting_facts.key: Hector Berlioz