Greek soprano born in the USA. During a dazzling career her voice and her unusual acting ability made her the prima donna assoluta of the 1950s and 1960s.
She left the USA in 1937 to study at the Athens Conservatory with Elvira de Hidalgo. In 1945 she returned to America and subsequently (1947) made a successful appearance at the Verona Arena as La Gioconda in Ponchielli's opera. This led to performances in the widely varying roles of Aida, Turandot, Isolde, Kundry, Brünnhilde, and Elvira (in I Puritani). Gradually, under the guidance of the conductor Serafin, she dropped the heavier roles and concentrated on earlier Italian opera and Verdi; she repeated the success of her debut at Covent Garden, singing Norma in Bellini's opera of that name (1952), with performances in Chicago and New York.
Musically and artistically Callas was a perfectionist. Her voice was strong, brilliant, and exciting but by the middle 1960s an increasing inequality of register and tremolo led to her retirement from the stage, her last Covent Garden performance being in Tosca in 1965. She gave masterclasses at the Juilliard School, New York (1971–72), and produced Verdi's Sicilian Vespers jointly with Giuseppe di Stefano (1973). She emerged from her retirement for an extensive world concert tour with di Stefano, which confirmed her undiminished artistic powers but revealed a voice past its prime.