Fiorenza Cossotto (born April 22, 1935) is an Italian mezzo-soprano. She is considered by many to be one of the greatest mezzo-sopranos of the 20th century. 　　Born on April 22, 1935 in Crescentino, Province of Vercelli, Italy, Cossotto attended the Turin Academy of Music and graduated top of her class. After her studies with Mercedes Llopart, she made her operatic debut as Sister Matilde in the world premiere of Poulenc's Dialogues of the Carmelites in 1957 at La Scala in Milan. Her international debut was at the 1958 Wexford Festival as Giovanna Seymour in Donizetti's Anna Bolena. Her Covent Garden debut was in 1959 as Neris in Cherubini's Médée, with Maria Callas in the title role. A 1962 performance of the lead in La favorita at La Scala led to wider fame and she made her American debut in the same role in 1964 at the Lyric Opera of Chicago and as Amneris at the Metropolitan Opera in 1968.