The Washington Opera, which was last heard from in November with Mozart's "Abduction From the Seraglio," resumes its sporadic existence this week with one of opera's most romantic creations, "I Capuleti e I Montecchi," by Bellini. The title means "The Capulets and the Montagues." But if you are planning to go to one of the performances on April 21, 23, 27, or 29, the first thing to do is to forget you ever heard of Shakespeare.

Oh, Tatiana Troyanos will bethere singing Romeo. And Linda Zoghby will do the same for Juliet. And the five-character cast includes a Tebaldo [Tybalt] sung by Antonio Savastano, Harry Dworchak as Capulet, and Julien Robbins as Laurence. (By the way, this Laurence is no friar, but a doctor.) But do not expect to see or hear from or about Mercutio, or Juliet's old and somewhat ribald nurse, or Paris, or any other characters from the Globe Theater. They won't be there.

Bellini's libretto is by his longtime friend and frequent collaborator, Felica Romani, who also provided him with the books for "Norma," "II Pirata," "La Sonambula," "Beatrica di Tenda," "La Straniera" and "Zaira." but working in great haste, Romani drew on various sources to remake a libretto which he had first written on the same subject for Nicola Vaccaj five years before. The haste was necessary because Bellini had accepted a commission for the new opera from the Teatro La Fenice in Venice, as he wrote to his friend, Gaetano Cantu: "The government and practically all of Venice has entreated me that, should Pacini not come to write the new opera, I must do it in only one month: they have all beseeched me to do this as a favor for Venice, which will be content with what I write in such a brief time."

When Pacini, with other fish to fry in Turin, defaulted on his agreement with Venice, Bellini, who had named an exorbitant fee for his new opera, set to work, having exactly six weeks from the time he started until the premiere of the new opera on March 11, 1830. Herbert Weinstock, Bellini's biographer, does not hesitate to claim, "It may not be too strong tosay that the composition of 'I Capuleti e I Montecchi" during the harsh Venetian winter of 1830 was a directly contributing cause of Bellini's death. It is more than possible that it was then that he contrated and began to suffer from the chronic amebiasis that would kill him in 1835."

Bellini's prophecy that Venice will be content with what I write" came true in spades! The audiences were reported "delirious in their enthusiasm!" over the new opera. It was repeated seven times in the 10 days left in the season.

Reasons for the enthusiasm are not hard to pin down. The libretto, concentrating on the bitter feud between the two families, who are often identified not only as Capulets and Montagues but also as Guelphs and Ghibellines, thus recalling a still more ancient speed to the secret promises of the two lovers - they do not marry in this opera - and to their subsequent separation.

Laurence - remember, he's a doctor - gives Juliet the sleeping potion. Romeo, returning, thinks she is dead and takes poison, dying just as she wakes from her long sleep. As the warring sides shout at each other over the two, Juliet dies of what must be called exhausion or sheer chagrin, since no other cause is discernible.

The opera has, as high points, solo scenes and duos for the lovers as well as major arias for Tybalt, or Tebaldo, early in the score. Completed just one year ahead of "Norma" with "II Pirata" and "I Puritani" to follow immediately thereafter, this "Romeo and Juliet" is in no way lessser Bellini.

Taking advantage of its longer occupancy of the Kennedy Center this season, the Washington Opera will introduce its other remaining subscription opera on Sunday afternoon, April 22, at 2 p.m., with repetitions on the 24, 26, 28.

Turning from tragedy, the company will offer one of the world's great comedy operas, Donizetti's "Don Pasquale," which is certainly making the rounds this season. Having been heard on a Metropolitan Opera Saturday afternoon broadcast, it will be back during the Met's Wolf Trap week in June. The Washington Opera is presenting it with Paolo Montarsolo in the title role, Barbara Daniels as Norina, Richard Stilwell as Dr. Malatesta, and Rockwell Blake as Ernesto. Theo Alcantara will take over the conducting duties which Nicola Rescigno will handle in Bellini.

One of the few elements in common between Bellini's tragedy and Donizetti's comedy is that of the haste in which both works were written. Donizetti's librettist, Giovanni Ruffini put it this way:

"Donizetti would like me to bring him pieces to set to music not every day, as I do, bur every hour; it will be beautiful, what's more. I've been eating up the paper, as they say. It's not a queation of doing it well or doing it badly, but of doing it fast."

By the time Donizetti wwrote "Donn Pasquale," he had finished over 60 operas, including "Linda di Chamounix," "La Favorita," "The Daughter of the Regiment," "Roberto Devereux" and his most famous opera, "Lucia di Lammermoor." By 1843 he could work where, when, and at whatever speed he chose.

From its overture to its sparkling finale, which ends with the moral, "To marry in old age is but weakness of mind," the music of "Don Pasquale" is top grade. The orchestration is particularly delicately handled, and the solo scenes, which reach a peak in Ernesto's serenade, "Com'e gentil," are sheer delight.

In these two operas, written just over a decade apart, different heights in the age of "bel canto" writing were reached. Both operas were favorite vehicles for the greatest singers of their day. They ha have returned to the opera stage as a rule when singers with the special virtures and techniques of that era became available. It is a purely unrelated coincidence that both composers died five years after writing these operas.