Maria Callas (December 2, 1923 – September 16, 1977) was an American-born Greek soprano and one of the most renowned opera singers of the twentieth century. She combined an impressive bel canto technique with great dramatic gifts. An extremely versatile singer, her repertoire ranged from classical opera seria to the bel canto operas of Donizetti, Bellini, and Rossini; further, to the works of Verdi and Puccini; and, in her early career, the music dramas of Wagner. Her remarkable musical and dramatic talents led to her being hailed as La Divina.
Elvira de Hidalgo (1892 - 1980), was a Spanish soprano and singing teacher, whose best-known student was Maria Callas. Of all Callas's teachers, de Hidalgo probably had the greatest influence on her technique and career. She was born in Valderrobres, Teruel Province (Spain). She had a significant singing career as a coloratura soprano before becoming a teacher at the Athens Conservatoire. She made several recordings for Columbia and Fonotipia. Her "Una voce poco fa" from Rossini's The Barber of Seville is typical of the singing of the excellently-trained singers of the turn of the century. Her timbre, ease of production and great agility are all hallmarks of the kind of singing technique which such teachers as Mathilde Marchesi taught in the late 19th century. She was not, however, a pupil of Marchesi but of Melchiorre Vidal, who also taught Maria Barrientos, Graziella Pareto, Julián Gayarre, Fernando Valero, Francesco Vignas and Rosina Storchio. She died in Milan, Italy in 1980.