Verdi was also responsible for a short four-act "Milan version" in which the first act was removed and the ballet omitted (performed in Milan in January 1884 in Italian translation) but also apparently approved a five-act "Modena version" in which the first act was restored but the ballet still omitted (performed in Modena in December 1886, also in Italian translation).

At its full length (including the ballet and the cuts made before the first performance), it contains close to four hours of music and is Verdi's longest opera.

After the ballet had been composed, it emerged during the 1867 rehearsal period that, without further cuts, the opera would not finish before midnight (the time by which patrons would need to leave in order to catch the last trains to the Paris suburbs).

In 1969, at a Verdi congress in Verona, the American musicologist David Rosen presented the missing section from the Philip-Posa duet from the end of Act 2, which he had found folded down in the conductor's copy of the score.

Additionally, the duet between Philip and the Inquisitor was shortened by four lines, and Elisabeth's aria in Act 5 consisted only of part of the middle section and the reprise.

[16] For the Rome premiere on 9 February 1868 at the Teatro Apollo, perhaps unsurprisingly, the Papal censor changed the Inquisitor into a Gran Cancelliere (Grand Chancellor) and the Monk/Emperor into a Solitario (Recluse).

[16][17] Following the unsuccessful performance in Naples in 1871, Verdi was persuaded to visit the city for further performances in November / December 1872,[18] and he made two more modifications to the score: (a) a revision of the closing two-thirds of the Philippe-Rodrigue duet in Act 2, Scene 2 (to Italian verses, almost certainly by Antonio Ghislanzoni[19]), which replaced some of the previously cut material, and (b) the removal of the allegro marziale section of the final Elisabeth-Carlos duet (replaced with an 8-bar patch).

In 1950, to open Rudolf Bing's first season as director of the Metropolitan Opera, the four-act version was performed without the ballet in a production by Margaret Webster with Jussi Björling in the title role, Delia Rigal as Elizabeth, Robert Merrill as Rodrigo, Fedora Barbieri as Eboli, Cesare Siepi as Philip II and Jerome Hines as the Grand Inquisitor.

[31] Also influential was a 1958 staging of the 1886 five-act "Modena version" in Italian by The Royal Opera company, Covent Garden, directed by Luchino Visconti and conducted by Carlo Maria Giulini.

The cast included Jon Vickers as Don Carlo, Tito Gobbi as Rodrigo, Boris Christoff as King Phillip and Gré Brouwenstijn as Elizabeth.

The cast included Mirella Freni as Elizabeth, Elena Obraztsova and Viorica Cortez as Eboli, José Carreras in the title role, Piero Cappuccilli as Rodrigo, Nicolai Ghiaurov as King Phillip, and Evgeny Nesterenko as the Grand Inquisitor.

The cast included Renata Scotto as Elizabeth, Marilyn Horne as Eboli, Giuseppe Giacomini as Don Carlo, Sherrill Milnes as Rodrigo, Nicolai Ghiaurov as King Philip, and James Morris as the Grand Inquisitor.

On 22 May 1973, the Opera Company of Boston under the direction of Sarah Caldwell presented a nearly complete five-act French version which included the 21 minutes of music cut before the premiere, but not the ballet.

The cast included John Alexander in the title role, the French-Canadian Édith Tremblay as Élisabeth, the French singer Michèle Vilma [fr] as Princess Eboli, William Dooley as Rodrigue and Donald Gramm as Philippe.

According to Andrew Porter, the Boston production was "the first performance, ever, of the immense opera that Verdi prepared in 1867; and in doing so it opened a new chapter in the stage history of the piece.

"[7][38] The BBC Concert Orchestra under John Matheson broadcast the opera in June 1973 with the roles of Don Carlos sung by André Turp, Philippe II by Joseph Rouleau, and Rodrigue by Robert Savoie.

[40] A co-production between the Théâtre du Châtelet in Paris and the Royal Opera in London in 1996 used Andrew Porter as a consultant and was a "judicious mixture" of music from the 1866 original and the 1883 revision.

The performance by the Paris cast (March 1996), was conducted by Antonio Pappano with Roberto Alagna as Don Carlos, Karita Mattila as Elisabeth, Thomas Hampson as Rodrigue, José Van Dam as Philippe II and Waltraud Meier as Eboli.

[46] The Houston production was conducted by Patrick Summers with Brandon Jovanovich as Don Carlos, Tamara Wilson as Elizabeth, Andrea Silvestrelli as Philippe II, Christine Goerke as Eboli, Scott Hendricks as Rodrigue and Samuel Ramey as the Grand Inquisitor.

[47][48][49][50][51] In 2017, the Opéra National de Paris performed the 1866 French version (before the ballet was composed) in a production staged by Krzysztof Warlikowski at the Bastille.

She reassures the people that her impending marriage to Don Carlos, Infante and son of Philip II, King of Spain, will bring the war to an end, and departs.

Carlos, coming out from hiding, has seen Elisabeth and fallen in love with her (Aria: "Je l'ai vue" / "Io la vidi").

When Carlos pauses in his lament, the leader of the monks proclaims that the turbulence of the world persists even in sacred places; we cannot rest except in Heaven.

The two men swear eternal friendship (Duet: "Dieu, tu semas dans nos âmes" / "Dio, che nell'alma infondere").

King Philip and his new wife, with their attendants, enter also to do homage at Charles V's tomb, while Don Carlos laments his lost love.

He orders the lady-in-waiting who was meant to be attending her, the Countess of Aremberg, to return to France, prompting Elizabeth to sing a sorrowful farewell-aria.

Scene 1: Evening in the Queen's garden in Madrid Elisabeth is tired, and wishes to concentrate on the following day's coronation of the King.

Their laments of suspicion cause the King to realize that he has been wrong to suspect his wife (Quartet: "Maudit soit le soupçon infâme" / "Ah, sia maledetto, il rio sospetto"[60]).

He adds that he is content to die if his friend can save Flanders and rule over a happier Spain (Aria, part 2: "Ah, je meurs, l'âme joyeuse" / "Io morrò, ma lieto in core").

They say a final farewell, promising to meet again in Heaven (Duet: "Au revoir dans un monde où la vie est meilleure" / "Ma lassù ci vedremo in un mondo migliore").