Once the performance has started, entry for latecomers is subject to the program: Approximate duration 2h 25 minutes with 1 intermission of 15 minutes. Tosca is an opera in three acts, with music by Giacomo Puccini and libretto in Italian by Luigi Illica and Giuseppe Giacosa. It is considered one of the most representative operas of the Italian verismo repertoire, due to its dramatic intensity and for containing some of the most beautiful arias in the repertoire. World premiere: Rome, January 14, 1900, at the Teatro Costanzi. Premiere in Mexico: July 1901, at the Teatro Arbeu. Premiere at the Palace of Fine Arts: March 1935.