Richard Wagner was a German composer and conductor who is best known for his operas. His works are considered to be some of the most influential in the history of opera. The four Wagner operas mentioned in the crossword solutions are Lohengrin, Parsifal, Rienzi, and Siegfried. Lohengrin is an opera in three acts that tells the story of a knight who must prove his innocence in order to win the hand of a princess. Parsifal is a three-act opera based on the medieval legend of the Holy Grail. Rienzi is a five-act opera about a Roman tribune who attempts to restore the republic. Finally, Siegfried is a three-act opera that follows the adventures of the hero Siegfried as he battles dragons and wins the hand of a princess.