Sandra Warfield performed with the Zurich Opera, where in 1961 she sang Katerina in the world premiere of Martinů's "The Greek Passion". They returned to the United States, and the Metropolitan Opera, in the 1960s. Her performances at the Met included Ulrica in Giuseppe Verdi's "Un ballo in maschera", Berta in "The Barber of Seville" by Gioachino Rossini, Marcellina in "The Marriage of Figaro", Maddalena in "Rigoletto" by Verdi and Erda in Richard Wagner's "Siegfried", totaling 172 performances. She sang the role of Delilah in "Samson and Delilah", with Richard Tucker performing as Samson. In her farewell performance in January 1972, Warfield
Gioachino Rossini twelve other Italian composers on a "Requiem for Rossini", to be performed on the first anniversary of Rossini's death, conducted by Angelo Mariani. The music was written, but the performance was abandoned shortly before its scheduled premiere. Verdi re-used the "Libera me, Domine" he had written for the Rossini Requiem in his 1872 "Requiem for Manzoni". In 1989 the conductor Helmuth Rilling recorded the original "Requiem for Rossini" in its world premiere. In 1900, Giuseppe Cassioli created a monument to Rossini in the Basilica of Santa Croce, Florence. The Library of the Royal Conservatory of Brussels possesses an important collection