Question: Which opera Ernani and Stiffelio.has more acts ?
Sentence (from "Gaetano Mares"): He notably conducted the world premieres of Giuseppe Verdi's "Ernani" (1844), "Attila (opera)" (1846), "Rigoletto" (1851) and "La traviata" (1853) at La Fenice in Venice.
Relevant evidence: No