Gluck composed Ezio for the Carnival in Prague in 1750, a dozen years before he entered his so-called “reform” era. The piece was a hit for a year or two, then (as was usual) forgotten, its music available for judicious recycling. But its success was no freak: This is an exciting score, waiting for the properly schooled forces to restore it to the stage. There have been several happy European revivals lately but none in America. 

Ezio was therefore an inspired choice for Boston’s feisty Odyssey Opera to open its “When In Rome” festival, which it did on Friday night in the hundred-year-old Boston University Theater, a beautifully restored 890-seat room across the street from Symphony Hall. Ezio will be followed on June 8, 10 and 12 by Mozart’s Lucio Silla, another neglected seria worthy of attention.

Gluck was thirty-five when he composed this score, and his operas had triumphed in Milan, Venice, London, Dresden and Vienna. There is little indication that he thought opera required reform, the grand simplification that produced (manifesto and all) the half dozen late works that are all we generally hear of his music: Orfeo, Alceste, Armide, the Iphigenias. Ezio is an opera seria, a formal string of arias on a well-known Metastasio libretto, with that richer, more personal flavor to their melodic declamation that one associates with the mature Gluck, the ancestor of Mozart, Cherubini, Berlioz and Wagner.

The opera was created for two heroic castrati, the great general, Ezio, and his neurotic emperor, Valentiniano; a major prima donna part for Fulvia, whom they both love, and—surprise!—a tenor for deceitful Massimo, Fulvia’s vindictive father. One might have expected a bass for a conspirator, or another castrato—but perhaps those voice ranges were thought too frank. Massimo is the subtlest, most striking figure in the opera, and Gluck revels melodically in the tortuous whorls of his mind.

Metastasio’s dramatic arcs are predictable. Since the opera opens with Ezio’s triumphant reception in Rome after defeating Attila the Hun, cheered by the crowds, honored by the monarch, the drama requires that Act II end with him in despair, abandoned and betrayed by all, cursing his destiny, the sort of pre-intermission soliloquy great castrati made famous. It’s a poignant moment in Handel’s or Porpora’s setting, but Gluck omits it. Perhaps his title singer was not good at this sort of thing. We don’t know.

All we know is what replaced it: A trio, “Passami il cor tiranno,” for the treacherous Massimo, the desperate Fulvia, the bewildered emperor, all of them expressing their emotions at the crisis (someone has tried to assassinate the emperor! If not Ezio, then who?), in a lengthy but swiftly paced summation, that Joshua Major has staged (as he staged the whole evening) with constant activity, the singers hurling themselves about the stage and into each other’s faces. This melodious elaboration (with a middle section in a contrasting key), this sung activity, is not what one expects from an opera of 1750; it sounds like Mozart thirty years later. It is the direction opera would take in the following century.

Equally startling to those familiar with Gluck is Massimo’s “Se povero il ruscello.” Not just the melody but the orchestration are old friends, “Che puro ciel” from Orfeo. We expect the sublime mood of Orfeo’s first sight of Elysium. But in this original setting, Massimo uses this heavenly tune to suggest to the emperor that Ezio may be disloyal: Power flows like a stream, but what if someone dams it? (Metastasian simile there.) The contrasting middle section leads the gullible tyrant to doubt.

As sung by William Hite, the melody becomes seductively evil, a lulling of conscience. Hite’s gracious, perfectly schooled instrument expressed the double face of treachery with deceitful tenderness throughout the opera; his singing was always perfectly produced, the meaning perfectly judged.

When Massimo wasn’t twisting the minds of the emperor and the hero, he was commanding his daughter to keep her mouth shut. Fulvia is a role for a dramatic prima donna with two enormous solo scenas in which Gluck piles on opportunities. The range runs both high and low, but Jennifer Holloway, who has gradually moved from mezzo to soprano parts, easily carried its demands. She began her long Act II self-examination lying on her back, a posture that miraculously did not interfere with breath control or intricate ornamentation.

The voice is sizable and flexible, and never becomes shrill under emotional pressure. Fulvia is under a lot of it; indeed, at eleven o’clock, when you think the plot is on course at last and there’s nothing much left to happen, Gluck tosses her a mad scene. Holloway triumphed with it. Bring on the Huns and Vandals; she can take ’em.

The castrati roles of emperor and the general were given one to a countertenor the other to a mezzo. Both solutions are valid. Randall Scotting sang the ignoble Valentiniano III. His voice is large and flexible, easily filling the house, but tends to a hootiness at the top and it took him a couple of scenes to find the proper pitch. By the time of the extraordinary trio, he was very much in gear, and the emperor’s aria of self-doubt was engagingly funny, his psychic state mirrored in leaps from low to high.

Scotting has a muscular physique and the director could hardly wait to get his toga off, an assassination attempt at the end of Act I providing the opportunity. One must be impressed by a singer who can perform coloratura while having his bare torso wrapped in bandages. New Yorkers will have a chance to hear him next week as Operamission’s Rinaldo.

Ezio was sung by mezzo Brenda Patterson with proper martial posture but she sang poorly, indefinite of pitch and with a thin, astringent sound that contrasted unhappily with the warm, clear tones of every other singer in the cast. Happily, Gluck seems to have anticipated this when he cut Ezio’s prison lament and gave him very little to do in Act III.

The emperor’s sister, Onoria, was sung by mezzo Erica Petrocelli, whose role was, I suspect, cut by a da capo or two. That’s a pity. She has an agile, faultlessly pitched mezzo of quality to make one wish cuts had been opened or opportunities seized. At one point she and Flavia, both in love with Ezio, exchange a few lines of pointed recit, and their snippiness got them laughs. Any later composer—Mozart, Ponchielli, Strauss—would have made hay with this and given us a jealous duet, and these two singers would have had a grand time with it.

Jesse Darden, a tenor who sings Belmonte, has a clear, silvery tenor far too good for the adjutant role of Varo, and his arias gave great pleasure.

The set by Jian Jung (stairs, square columns) and the costumes by Rachel Padula Shufelt (basic black, purply shmattas for the royals) implied that Odyssey’s budget was being saved for the musicians, as is proper. You had to imagine late imperial Rome. We’ve all seen movies; we can do this. We didn’t have to imagine great music, because the musicians took care of that.

Gil Rose, the artistic and general director of Odyssey, led an orchestra of nineteen: oboes, horns and strings. The story’s mood-swings, each tune drawing its proper accompaniment, proceeded swiftly and clearly, the dramatic confrontations were effective, and he had no trouble communicating with singers who were upstage or lying down or writhing in psychological agony. Rose had already won my heart with his choice of repertory (in the fall, he’s presenting Dvorak’s Dimitrij, imagine that!), but the care and momentum of his Ezio and his taste in singers make Odyssey a company that bears close attention from all the opera lovers in the northeast.

Photo courtesy of Odyssey Opera.