WHEN ROBERT LOWELL died in September, 1977, at age 60, he left behind only a small bundle of material that had not yet been published: a remnant scattering of poems, a handful of essays, and this ancient Greek triptych -- his rendition of the Oresteia of Aeschylus.

Accoring to a brief introduction provided by his literary executor, Frank Bidart, the origin of Lowell's efforts to render this trilogy dates to the early 1960s, when New York's Lincoln Center Repertory Theater considered producing an earlier Lowell version of Agamemnon , the first and best of these three plays. Although plans for that project fell through, they were revived briefly a decade later by producer Joseph Papp. Encouraged by Papp's intervention, Lowell not only revised the Agamemenon but set to work translating the remaining brace of plays. Papp was soon forced to abort the project, but it was clearly the expectation of production that encouraged the poet to complete the work.

No stranger to the stage, Lowell had pieced together his 1964 trilogy, The Old Glory , from short stories by Hawthorne and Melville. Translations of Racine's Phaedra and Aeshylus' Prometheus Bound also provided an attractive alternative to the night sweat of his poems. Of these productions, only the Aeschylus received a consistently favorable critical reception. Laden with moral implications and psychological innuendo, power and passion, the Greek tragedy suited Lowell's dynamic literary style. Then, too, translation (or "imitation," as he calls it) was a medium of expression that had fascinated him from the beginning of his career. In his own right he had managed to make rendition a new, living from of art.

Characters are everything in the theater, and as any playwright worth his salt knows, you cannot create vivid characters without a strong flow of action to define them. Packed with action, the Oresteia recreates a succession of crimes and their retribution in the house of Atreus. The action starts before the events of Agamemnon get under way, when Atreus denies his brother Thyestes his rightful line of ascent to the throne of Argos. Thus begins a flood of misadventures that in the first two plays -- Agamemnon and Choephoroe (Orestes in Lowell's version) -- culminates in the death of three principals. A trail of bloody footprints gets bloodier and harder to follow: Thyestes's son Aegisthus and Agamemnon's wife, Clytemnestra, conspire to murder Agamemnon and seize the throne. Orestes than murders his father's murderers, including his mother Clytemnestra. The final play, Eumenides (The Furies ), finds Orestes on trial as the Olympian deities debate the morality of the very crime that they ordained -- a not unheard-of contemporary plot.

Contemporaneity, for that matter, is what the Oresteia boasts in greatest profusion. War, politics, murder, revenge, and domestic intrigue yoke act to act, play to play. In the central character of Orestes we have the classic example of the tragic hero caught between conflicting sanctions: ordered by Apollo to avenge the murder of a king, he must either murder his mother or betray the gods. He can evade neither the choice nor its consequence.

Essentially, however, it was the stirring yet subtle poetry of Aeschylus that intrigued Lowell. In a short prefatory note, he spells out his modest proposal to "to trim, cut, and be direct enough to satisfy my own mind and at a first hearing the simple ears of a theater audience."

Although drestically reduced, there remain too many long lyric exchanges between characters, particularly in Orestes . These lengthy perorations, consisting mainly of prayers and invocations, look somewhat lame in translation. On the other hand, it can probably be argued that they are necessary from a historionic point of view insofar as they help prepare the audience for the ghastly enactment of matricide, the spectacle's fulcrum. This built-in weakness aside, Lowellhs modification of the trilogy is naturalistic, simple, not flowery. There is none of the flash here of a Shakespeare or Marlowe, no memorable soliloquies or orations, but that is not Lowell's intention. His language is squat, for the most part, and constructed with commonplace solidarity. There is a deliberate retreat from the fireworks generated by his earlier lapidary efforts. The power and passion are subdued and therefore all the more sinister.

Always in his translations, Lowell has been interested in rendering a certain world, a mode of sensibility. The emphasis is on mood and tone, not on the literal meaning of words. As in his volum Imitations , he has tried to write a living English and to do what Aeschylus might have done had he written these dramas now and in America. In his delirium, following the heinous act of revenge, Lowell's Orestes sounds as au courant as Muhammad Ali: "I feel my heart pounding like a boxer's/ weighted fist on my ribs. Always/ the beat is rising, as if I led the singers/ in the dance of anger through Argos to their deaths."

This is a strange, upbeat vernacular for ears more accustomed to the slow perambulation of what today passes for conventional Greek tragedy. As against translation, it is transubstantiation that Lowell seems to be after -- an attempt to recreate in another idiom the essential effect of the original idiom. And while this method of rendition -- psychological and intuitive rather than objective and textual -- may alarm the pedants, it lends itself much more readily for adaptation to the modern stage.

More problematic is Lowell's startling confession at the fore that "I do not want to cry down my translations, but to say what I've tried to do and not tried. I have written from other translations and not from the Greek. One in particular, Richmond Lattimore's, has had my admiration for years, it is so elaborately exact." That, of course, speaks well for Lattimore, less well for Lowell. It is one thing to translate for mood and not accuracy of text; it is another thing to improve translations of Aeschylus by intermediaries. When one translates not from the original but from another's translation of the original, all true sense of meter and rhythm is inevitably lost; the sound and shape of words in the original remain out of reach. All that is left is the "sense," the literal "meaning" of the original. What we appear to have here, then, is not Lowell translating Aeschylus, but Lowell translating Lattimore, which makes it a whole new ballgame.