Question: A Life for the Tsar is a  Russian libretto with four acts, Tosca an Italian libretto has how many acts?
Sentence (from "A Life for the Tsar"): The original Russian libretto, based on historical events, was written by Nestor Kukolnik, Egor Fyodorovich (von) Rozen, Vladimir Sollogub and Vasily Zhukovsky.
Relevant evidence: No