Question: Were Pietro Mascagni and Ambroise Thomas both best known for their contrabution to theatre? 
Sentence (from "Pietro Mascagni"): Pietro Antonio Stefano Mascagni (] ; 7 December 1863 – 2 August 1945) was an Italian composer most noted for his operas. His 1890 masterpiece "Cavalleria Rusticana" caused one of the greatest sensations in opera history and single-handedly ushered in the "Verismo" movement in Italian dramatic music.
Relevant evidence: Yes