[6] She was born at Flower Fifth Avenue Hospital (now the Terence Cardinal Cooke Health Care Center) on December 2, 1923, to Greek parents, George Kalogeropoulos (c. 1881–1972) and Elmina Evangelia "Litsa," née Demes, originally Dimitriadou (c. 1894–1982).

[19] Litsa, beginning in New York and continuing in Athens, had adopted a questionable lifestyle that included not only pushing her daughters into degrading situations to support her financially but also entertaining Italian and German soldiers during the Axis occupation.

In 1957, Trivella recalled her impression of "Mary, a very plump young girl, wearing big glasses for her myopia": The tone of the voice was warm, lyrical, intense; it swirled and flared like a flame and filled the air with melodious reverberations like a carillon.

[26]However, when interviewed by Pierre Desgraupes on the French program L'invitée du dimanche, Callas attributed the development of her chest voice not to Trivella but to her next teacher, the Spanish coloratura soprano Elvira de Hidalgo.

On April 2, 1939, Callas undertook the part of Santuzza in a student production of Mascagni's Cavalleria rusticana by the Greek National Opera at the Olympia Theatre, and that autumn she enrolled at the Athens Conservatoire in Elvira de Hidalgo's class.

"[25] Fellow singer Maria Alkeou similarly recalled that the established sopranos Nafsika Galanou and Anna (Zozó) Remmoundou "used to stand in the wings while [Callas] was singing and make remarks about her, muttering, laughing, and point their fingers at her".

[29] Michael Scott's words, "the notion of any one singer embracing music as divergent in its vocal demands as Wagner's Brünnhilde and Bellini's Elvira in the same career would have been cause enough for surprise; but to attempt to essay them both in the same season seemed like folie de grandeur".

"[21] After the performance, one critic wrote, "Even the most sceptical had to acknowledge the miracle that Maria Callas accomplished ... the flexibility of her limpid, beautifully poised voice, and her splendid high notes.

[28] La Scala mounted many new productions specially for Callas by directors including Herbert von Karajan, Margherita Wallmann, Franco Zeffirelli and, most importantly, Luchino Visconti.

"[40] Her Metropolitan Opera debut, opening the Met's seventy-second season on October 29, 1956, was again with Norma,[41] but was preceded by an unflattering cover story in Time magazine, which rehashed all of the Callas clichés, including her temper, her supposed rivalry with Renata Tebaldi, and especially her difficult relationship with her mother.

[citation needed] In 1952, she made her London debut at the Royal Opera House in Norma with veteran mezzo-soprano Ebe Stignani as Adalgisa, a performance which survives on record and also features the young Joan Sutherland in the small role of Clotilde.

[31][page needed] It was at the Royal Opera House where, on July 5, 1965, Callas ended her stage career in the role of Tosca, in a production designed and mounted for her by Franco Zeffirelli and featuring her friend and colleague Tito Gobbi.

He avers that like Pasta and Malibran, Callas was a natural mezzo-soprano whose range was extended through training and willpower, resulting in a voice which "lacked the homogeneous color and evenness of scale once so prized in singing.

[53] Ardoin points to the writings of Henry Chorley about Pasta which bear an uncanny resemblance to descriptions of Callas: There was a portion of the scale which differed from the rest in quality and remained to the last 'under a veil.' ...

Ah parli a un core" from I vespri siciliani to E-natural (E6) above high C (C6), heard in the aria "Mercè, dilette amiche" in the final act of the same opera, as well as in Rossini's Armida and Lakmé's Bell Song.

"[47] And as she demonstrated in the finale of La sonnambula on the commercial EMI set and the live recording from Cologne, she was able to execute a diminuendo on the stratospheric high E-flat, which Scott describes as "a feat unrivaled in the history of the gramophone.

"[48] While reviewing the many recorded versions of "perhaps Verdi's ultimate challenge", the aria "D'amor sull'ali rosee" from Il trovatore, Richard Dyer writes, Callas articulates all of the trills, and she binds them into the line more expressively than anyone else; they are not an ornament but a form of intensification.

She sees the aria as a whole, "as if in an aerial view", as Sviatoslav Richter's teacher observed of his most famous pupil; simultaneously, she is on earth, standing in the courtyard of the palace of Aliaferia, floating her voice to the tower where her lover lies imprisoned.

"[59] Walter Legge states that, Most admirable of all her qualities, however, were her taste, elegance and deeply musical use of ornamentation in all its forms and complications, the weighting and length of every appoggiatura, the smooth incorporation of the turn in melodic lines, the accuracy and pacing of her trills, the seemingly inevitable timing of her portamentos, varying their curve with enchanting grace and meaning.

[47]Regarding Callas's acting ability, vocal coach and music critic Ira Siff remarked, "When I saw the final two Toscas she did in the old [Met], I felt like I was watching the actual story on which the opera had later been based.

She was eminently capable of the grand gesture; still, judging strictly from the evidence of her recordings, we know (and her few existing film clips confirm) that her power flowed not from excess but from unbroken concentration, unfaltering truth in the moment.

"[59] Opera director Sandro Sequi, who witnessed many Callas performances close-up, states, "For me, she was extremely stylized and classic, yet at the same time, human—but humanity on a higher plane of existence, almost sublime.

"[67] Italian critic Eugenio Gara adds: Her secret is in her ability to transfer to the musical plane the suffering of the character she plays, the nostalgic longing for lost happiness, the anxious fluctuation between hope and despair, between pride and supplication, between irony and generosity, which in the end dissolve into a superhuman inner pain.

The most diverse and opposite of sentiments, cruel deceptions, ambitious desires, burning tenderness, grievous sacrifices, all the torments of the heart, acquire in her singing that mysterious truth, I would like to say, that psychological sonority, which is the primary attraction of opera.

[21][59] Commercial and bootleg recordings of Callas from the late 1940s to 1953—the period during which she sang the heaviest dramatic soprano roles—show no decline in the fabric of the voice, no loss in volume and no unsteadiness or shrinkage in the upper register.

[36][page needed] Of her December 1952 Lady Macbeth—coming after five years of singing the most strenuous dramatic soprano repertoire—Peter Dragadze wrote for Opera, "Callas' voice since last season has improved a great deal, the second passagio on the high B-natural and C has now completely cleared, giving her an equally colored scale from top to bottom.

[36][page needed] Soprano Renée Fleming posited that videos of Callas in the late 1950s and early 1960s reveal a posture that betrays breath-support problems: I have a theory about what caused her vocal decline, but it's more from watching her sing than from listening.

What is noticeable, however—earlier this season in Verdi's La Forza del Destino and now in Tosca—is a marked thinning of quality at the very center of the instrument, together with a slight acidity and tightening of the tone that has definitely taken the youthful bloom off, especially at the top.

A live television transmission of act 2 of the Covent Garden Tosca of 1964 was broadcast in Britain on February 9, 1964, giving a rare view of Callas in performance and of her on-stage collaboration with Tito Gobbi, directed by Carlo Felice Cillario.

[84] In 1957, while still married to husband Giovanni Battista Meneghini, Callas was introduced to Greek shipping magnate Aristotle Onassis at a party given in her honor by Elsa Maxwell after a performance in Donizetti's Anna Bolena.