She wasn't the last of the first movie stars, nor the most popular, but she was a living epitome of an epoch now gone, and her death gives the lie, rather cruelly, to the illusion of agelessness she represented both on the screen and off it.

The passing of Gloria Swanson yesterday at 84 depletes the ranks of American royalty, the royalty that once filled the world's filmic dreams, and it severs another link with the closest thing this century has to a romantic age: the glory and the vanity that was Hollywood at its palmiest.

Miss Swanson was there for those brave beginnings, and she appears to have been as brave as they were--by her own accounts and others--a feisty, spirited, determined, perhaps prematurely liberated woman who usually knew what she wanted, rarely may have known what was best for her, got plenty of both. She was a sex symbol of one day, a Great Lady of another, but her most triumphant moment on the screen was when she played a fearlessly self-effacing parody of herself, or the image that legend may have fashioned for her: Norma Desmond, aging queen of the silenced silent screen, in Billy Wilder's "Sunset Boulevard."

That was the film in which Miss Swanson uttered, among other lines quoted liberally by film followers, the assertion, "We had faces then," a reference to the arty-glamoroso superiority of the silent screen days over the vulgarities of the talkies that followed. Publicist John Springer, a longtime scholar of Hollywoodiana, called his 1974 book about movie stars of the past "They Had Faces Then," and Springer said yesterday that Miss Swanson was one of the faces that became indelible.

"Except for Blanche Sweet and Lillian Gish, she's the end of an era," Springer said of Miss Swanson. "Lillian Gish was a little ahead of Miss Swanson, but Blanche Sweet pretty much dropped out of films when sound came in; they are both still with us. But Gloria Swanson was present in virtually every era of motion pictures."

When Miss Swanson came to Hollywood in 1916, there barely was a Hollywood there. Her first roles were in two-reelers at Mack Sennett's comedy factory. In later years, Miss Swanson emphatically tried to scotch the tale that she had been, like so many other chorines in the Hollywood of that day, a Mack Sennett "Bathing Beauty."

She decided to write an autobiography, "Swanson on Swanson," because, she said in 1974, "It will give me a chance to correct a lot of errors. Like that rumor that I was a Mack Sennett bathing girl. I was never a Mack Sennett bathing girl. But when I die, and I'm lying in the morgue, they'll say I was. Why, I wouldn't even swim! When I went to a party at Mary Pickford's and they threw me into the pool, they all thought it was very funny when I was screaming for help. I was serious!"

For the record: Miss Gloria Swanson was not a Mack Sennett bathing girl. Miss Gloria Swanson was Miss Gloria Swanson.

When the book finally appeared in 1980 (copyrighted by Gloria's Way Inc.), Miss Swanson rakishly did confirm other rumors, the most newsworthy among them that she'd had a romantic as well as business relationship with Joseph P. Kennedy, the quintessential American patriarch, and a wealthy dabbler in the movie business. Surely a part of Miss Swanson's credo, handed down to her from the dawn not only of Hollywood but of Hollywood ballyhoo (author David Shipman, in his book "The Great Stars," called her "the first film player to be fully aware of the full value of publicity") was the commandment that one does not let one's public down. And so, in the book, in terms as gaudy and purple as were somehow nuttily appropriate, she recalled her seduction by Kennedy:

"He moved so quickly that his mouth was on mine before either of us could speak. . . . Apart from his guilty, passionate mutterings, he had still said nothing cogent."

It isn't being unkind to wonder if the screenplay Norma Desmond fancifully composed for her comeback, in "Sunset Boulevard," might have sounded something like that passage. Miss Swanson was among the first people on earth to experience the sensation of being made larger than life by a few tricks of light, reflection and projection; her real life was bound to be affected by the grandness of this new illusion.

In person, however, Miss Swanson was beguilingly diminutive. Visiting Washington to film a cameo appearance in the little-remembered movie "Airport 1975," Miss Swanson, then 75, was discovered by a reporter sitting in an out-of-the-way lounge in a nearly deserted nook at Dulles Airport, accompanied by a young man who was, among other things, the custodian of jars of her health foods, the virtues of which she never tired of extolling.

Though hidden by a veil and wearing white gloves, Miss Swanson seemed defiantly youthful and vivacious. There was about her the most commanding aura of delicacy, a delicacy almost ethereal and yet one that conveyed not a hint of weakness. She talked matter-of-factly about practical things like bees' honey and wheat germ, and rummaged for things in her purse, and one easily could see how she might have used her tininess in shrewd and intimidating ways over the years.

Miss Swanson, who had not made a movie since 1952 (but had made occasional appearances on television) said she was playing herself in this picture because, well, who else should she play? "Why play any old actress?" she asked rhetorically. "I'm an awful mimic. It's more of a challenge to play yourself. I never really knew how I walked, how I talked, whether I did gestures like--oh, what's-her-name?--Bette Davis."

When her career began, Miss Swanson is alleged to have declared, "I have decided that when I am a star, I will be every inch and every moment the star. Everybody from the studio gateman to the highest executive will know it." As Norma Desmond, she revisited Paramount Studios thinking DeMille himself was interested in reviving her career, when in fact it was only her old car that was wanted for a spot in a film. DeMille played himself in the picture. In real life, he had directed Miss Swanson years earlier, but never gave her prominent billing and declared in his own autobiography, "The public, not I, made Gloria Swanson a star."

And this was when people were stars for longer than 15 minutes.

In "Sunset Boulevard," Norma Desmond is noticed on a Paramount sound stage by a technician in the rafters who had worked with her years earlier, before the intrusion of talkies. He turns one of the huge klieg lights toward her, and shouts at her, and she puts a hand above her eyes and squints up at him, into the blinding glare. This was the light in which Gloria Swanson as well as Norma Desmond bathed, and luxuriated, and thrived. "Norma Desmond? You used to be big," William Holden had said in "Sunset Boulevard," and Norma Desmond replied, "I am big. It's the pictures that got smaller."

Gloria Swanson was among the last of the great movie divas, and more than many of her contemporaries, she remained, apparently to the end, pretty magnificent in the role of herself.