Opera impresarios from around the country -- New York, Seattle, Miami and other cities -- were in the Kennedy Center Opera House Saturday night for the long-heralded revival of Italo Montemezzi's great work, "L'Amore dei Tre Re." They were rewarded with what was, in most respects, a triumphant restoration of a work that is already scheduled to enjoy a long-overdue and highly deserved return to major opera stages.

Hearing "L'Amore" again after a long time away from it confirms a conviction of its greatness and reinforces its position as a towering music drama whose psychological impact seems more powerful than ever. Mondtemezzi's music moves on an extraordinary level of intense beauty that mirrors the violent emotions on the stage. The Washington Opera production is successful in matching its unusual auditory and visual demands.

First place of honor goes to conductor John Mauceri who has obviously steeped himself in the score to the point where he conveys with overwhelming effect the subtle beauties as well as the tremendous climaxes of the music. He drew lustrous playing from the orchestra which responded with some of the best playing in its history. The fluidity in Mauceri's tempos, conforming to the composer's frequent and specific markings, provided the mounting tension that can come only from the conductor.

"L'Amore" is an opera that requires four great singing actors. The Washington Opera is fortunate to have three. Foremost is Jerome Hines in the monumental pivotal role of Archibaldo. From his initial entrance he foreshadowed every aspect of the human tragedy that followed. His acting of the old blind king was of shattering power, culminating in terrifying second-act curtain that left the audience limp. (And the curtain came down just seconds too soon.) Hines, who made his operatic debut 40 years ago, is a miracle of singing and acting. His voice reflected every nuance of the grand part in a way that won him a vast personal triumph.

Opposing him as Fiora, Carol Neblett offered a woman so blinded by passion that she willingly gave herself over to love and eventually to death. Neblett's entire demeanor was suffused with the torment of loving one man while married to another four whom she felt no love at all. Her voice was thrilling at the top and sensuous in the low range where so much of import lies. Her opening scene, beautifully done, would be still more effective if she would take more phrases at their softest. And she must make far clearer her great cries of "Indicibile contrasto!" and "Ah! tortura!"

One of the great achievements in the performance is the magnificent singing of the hitherto little-known baritone Charles Long. What a treasure! His voice, flawlessly produced, is a clear, ringing instrument of rich, beautiful power, capable of heroic passion and touching sympathy, both of which he uses devastatingly as the innocent Manfredo. Here is an artist of marvelous bearing who can be called ideal, one who should hear at every opportunity. He, too, can add final touches: His cry of "Morta!" when told of Fiora's death must be more wrenching and the subsequent "Che di tu?" equally empathic.

It is an unhappy fact that James McCray is miscast as Avito. It seems unlikely that he has the voice for the part; certainly on Saturday night it was not working for him. While there were good moments, there was neither the requisite power nor the dramatic responses. You would never have known that after kissing Fiora's poisoned lips, he was dying, a fact that Long, in the same situation a moment later, made instantly clear.

John Gilmore sang and acted an admirable Flaminio, a minor but crucial role, while each of the brief roles in acts two and three was equally well-done.

The direction of Montemezzi's masterpiece is of crucial importance, and Frank Corsaro must be praised for the superb manner in which he laid bare the essential motivations of the work. There was genius in his handling of Fiora's veil, that fragile symbol with which she waved to her departing husband, which later bound her to her lover and finally became a frail weapon to taunt her blind father-in-law. Each new pairing -- lovers, husband and wife, father and son, and above all, the final fatal confrontation of the old king and the deceiving wife -- was convincingly projected. Aside from Fiora's premature descent to Avito, which should not occur until after she has permitted him to touch the hem of her garment, the staging was ideal.

Beni Montresor's sets and costumes made an appropriately rich series of gorgeous medievel portraits in stunning colors. There were certain overdone touches in the final act: Twenty flaring candles should not distract the audience by their threats to the safety of several characters on the stage, and a slightly less-yellow light in act two would be more effective. And surely Manfredo should wear some hint of armor in the second act. A silk robe is hardly what the warrior wears when departing for battle.