Question:  Les nuits d'été is a song cycle by a romantic composer who made significant contributions to the modern orchestra with what?
Sentence (from "Hector Berlioz"): Louis-Hector Berlioz (] (English: ); 11 December 1803 – 8 March 1869) was a French Romantic composer, best known for his compositions "Symphonie fantastique" and "Grande messe des morts" (Requiem).
Relevant evidence: Yes