Un Ballo in Maschera (1956);

Callas's first stage appearances in Verdi's Un ballo in maschera came at La Scala in 1957, a year in which Milan also saw her in La sonnambula and Anna Bolena. As in this recording, made the year before, she shared Verdi's most spectacular soprano-tenor duet (in Act II) with Giuseppe di Stefano. This was the last time Callas and Di Stefano appeared together in opera, though they reunited in the 1970s to direct I vespri siciliani in Turin and to give a series of joint concerts in Europe, the USA, Canada, South Korea and Japan. Gramophone judged this recording of Ballo to be 'one of Callas's most compelling assumptions'.