In Le Monde, the well-known critic Jacques Lonchampt praised her dark, velvety mezzo, her artistry and technique, as well as her glittering beauty on the stage.

After being hired by the Romanian National Opera in Bucharest in 1967, this changed, as she toured the country and Europe (the former Yugoslavia, France, Greece and especially Ireland), making her debut in Ambroise Thomas' Mignon, Giuseppe Verdi's Don Carlo, Aida and Il trovatore, Gaetano Donizetti's La Favorita and Jules Massenet's Werther.

She performed in Philadelphia, Pittsburgh, then finally New York, where she first appeared alongside Martina Arroyo in Verdi's Messa da Requiem in Carnegie Hall.

In Milan, succeeding Shirley Verrett's Dalila, Cortez was asked by the opera management and conductor Georges Prêtre to consider an extra performance, an exceptional decision of the theatre following the enormous success of her first appearance with the house.

The celebrated Bulgarian bass was her partner for Massenet's freshly revived opera, Don Quichotte, both in Paris and Chicago, the Parisian mise en scène being assigned to Peter Ustinov.

She portrayed a rapturous Dalila (Teatro Sao Carlos, Lisabona - 1975, Grand Opera, Paris - 1978), a powerful, intense Azucena (Metropolitan, New York - 1973, 1977, 1978, Grand Opera, Paris - 1975, Staatsoper, Vienna - 1973, 1974, 1976, Teatro alla Scala, Milan - 1978), a fragile Charlotte in Massenet's Werther, almost always with Alfredo Kraus, who named her his "absolute favourite Charlotte", a dramatic Eboli, notably in Vienna, Bordeaux, Lisbon, Bilbao and for La Scala Bicentennial - 1978, a delicate and interiorised Marguerite in Berlioz's La Damnation de Faust (Paris, Verona), and a sovereign and shining Amneris (La Scala, Milan - 1973, Arena di Verona - 1977, Metropolitan, New York - 1979).

She felt no boundaries or shyness in jumping from one composer to another, mixing Monteverdi (L'Incoronazione di Poppea, Naples, 1976) with Giordano (Fedora, Bologna, 1977), Stravinsky (Oedipus Rex, La Scala, Milan, 1972, 1973, 1980) with Mussorgsky (Boris Godunov, Paris, 1980), Rossini (Tancredi, Martina Franca, 1976) with Lalo (Le Roi d'Ys, Nancy, 1979).

For almost four years, she was rarely in Europe, due to her long-term Metropolitan engagements (Samson et Dalila - 1981, Il Trovatore, Les Contes d'Hoffmann, Adriana Lecouvreur - 1982, 1983, 1984).

She sang in Denver, Rio de Janeiro, Madrid, Bagdad, Tokyo, Osaka, and Amsterdam, but she also returned to stages such as L'Arena di Verona (La Gioconda and Aida - 1988), Grand Opera, Paris (Herodias in Richard Strauss' Salome in the fascinating mise-en-scene of her dear Jorge Lavelli), Gran Teatre del Liceu, Barcelona (Il Trovatore, La Gioconda, Les Contes d'Hoffmann, Il Matrimonio Segreto - 1986, 1987, 1988, 1989), Teatro Comunale di Bologna (Un Ballo in maschera with Luciano Pavarotti - 1989).

From the middle of the 1980s, Cortez, extremely conscious of the status of an artist of her calibre, started to abandon the prima donna roles in favour of more mature, real-life and age correspondent parts.

After almost six months of recovery, she returned to the stage (La Comtesse de Coigny and Madelon in Giordano's Andrea Chénier in Seville), determined to pursue her career.

Subsequently, as a confirmation of the very special relationship between the singer and the Spanish audience, she concentrated most of her career in Barcelona, Madrid, Sevilla, and Bilbao, without neglecting offers from Italy or France.

At the Gran Teatre del Liceu, she added to her repertoire a role she had been dreaming of since the 80s: The Old Countess from Tchaikovsky's The Queen of Spades, which she reprised in Madrid (Teatro Real, 2004).

She also reprised one of her best recent characters, Madame de Croissy, in Les Dialogues des Carmelites, for the opening of the 2008–2009 season at Teatro Campoamor in Oviedo, in the famed production of Robert Carsen.

She sang the opera 278 times, more than Gianna Pederzini or Giulietta Simionato, and since her big Covent Garden break (1968), she relentlessly deepened the character, almost identifying herself with Mérimée's and Bizet's heroine.

The critics applauded her creamy, very extended voice, able to cover all three registers, her exquisite technique, her refinement in the French way of punctuating, as well as her breathtaking beauty and charisma on stage.

The first international one, made for EMI France, was maybe another missed step: Mercedes in Carmen alongside Grace Bumbry, Jon Vickers, Mirella Freni and Kostas Paskalis, under the baton of Rafael Frühbeck de Burgos.

She then had the chance of recording Azucena in Il Trovatore with Bruno Bartoletti and Maddalena in Rigoletto with Francesco Molinari-Pradelli, both operas being filmed for German television.

The lack of official recordings kept Cortez one step behind her illustruous colleagues Fiorenza Cossotto, Grace Bumbry, Shirley Verrett or Elena Obraztsova.

Fortunately, the last decade brought a flourishing of in-house live recordings: Oberto, conte di San Bonifacio (Bologna, 1977), Aida (Vienna, 1973, Denver, 1986), Elektra (Rome, 1971), Norma (Naples, 1973, Caracas, 1975), Maria Stuarda (Chicago, 1973), Il trovatore (Paris 1975, New York 1978, 1981), La favorita (Genova, 1976), Don Carlo (Milan, 1978), Adriana Lecouvreur (New York, 1983), Gioconda (Verona, 1988), Suor Angelica (Madrid, 1993), Zaza (Palermo, 1994), La fille du régiment" (Madrid, 1996), Les contes d'Hoffmann (Orange, 2002), Jenůfa (Barcelona, 2005).

Viorica Cortez was married three times: first, to the Romanian sculptor Marcel Guguianu, then to the French composer Emmanuel Bondeville, former manager of the Paris Opera and Opéra Comique, and finally to the Romanian-born historian Adolf Armbruster.