RIVIERE-DU-LOUP, QUEBEC -- This is a story about a family reunion in Quebec where 1,400 people showed up.

What sort of family would have 1,400 people show up at a reunion? Mine. The kind of family that's not so much a family as a political machine. In 1986, some folks in Quebec, where the family hails from, organized a group called L'Association les Dionne D'Amerique Inc. I got a mailing from them a few years back and decided: At last, a special interest group I can support unreservedly.

So please do not expect a fair-minded, objective account. I will be utterly dispassionate about Republicans and Democrats, liberals and conservatives, vegetarians and beef ranchers. But we're talking here about my roots. Did you ask Alex Haley to be objective?

The Dionne Association most certainly isn't, but it's terribly serious about genealogy, heritage and all that. It even puts out a quarterly journal called La Voix des Dionne that includes articles with titles like: "Jean Dionne, Known as Sanssoucy, Was He the Father of Antoine?"

Don't scoff. In the course of the weekend reunion, I learned that questions like that are not trivial. If the Dionne Association has an ideology, it might be called Antoinism. The idea is that virtually everyDionne in North America descends from the same ancestor, Antoine Dionne, who came to Quebec from France in 1663. That means I can finally give an answer to a question I've been asked all my life: Yes, I am related to the Dionne Quintuplets, through Antoine at least.

I also learned that Antoine and Catherine Ivory, his wife, had 12 children, but only six survived, including only one son, Jean Dionne (1670-1752). So we all descend from Jean too, and "The Great Dionne Gathering of America," held here Aug. 4-5, was designed as a celebration of the 320th anniversary of Jean's birth.

I was suspicious at the beginning of Antoinism, and its corollary, Jeanism. I kept thinking of some poor Dionne way back there whom we've cast into the dustbin of genealogy. But the organizers were quite convincing about all the work they'd done to establish the truth of Antoinism.

Besides, the sense of solidarity created by a common ancestor was nothing to sneer at. Never had I been to a convention where the words "we" and "us" carried quite the same meaning. When I apologized to someone I collided with in the lobby, he just gave me a broad grin. "Don't worry," he said. "We're all Dionnes here." That doesn't happen at the local Safeway.

To get all these people together, the Dionne Association mailed invitations to every Dionne in every phone book in North America; about 6,000 pieces of mail were sent out last winter. When I got mine, my reporter's instinct was to sense a scam. But with a $50 registration fee for the weekend, I figured there wasn't much money to be made. Besides, when a Dionne I met in the lobby found out I was a reporter, he made me promise that I wasn't there pursuing a story about "Dionnegate." I promised, so forget about the scam angle.

It turned out that this sort of reunion, while unusual, was not unprecedented for families in Quebec.. Giles Dionne, president of the Association, said that popular interest in genealogy and family history has grown over 15 years side-by-side with the resurgence of Quebec nationalism.

But Giles, a former official of the Quebec Ministry of Education, said the main motivation lay in "the search for identity" that seems to so preoccupy modern men and women. "We can't find our identity without returning to our roots," he said.

FranceDionne, who represents this area in the Quebec National Assembly, said the Dionnes were slow to organize compared with some other large Quebec families, like the Ouelettes and the Tremblays. She said she welcomed the Dionnes' coming of age organizationally, but didn't expect all that much political benefit herself. A shrewd vote counter, she said the Dionnes were too scattered to be all that much of a block.

The Dionnes came to Riviere-du-Loup from just about everywhere -- from all over Quebec and Canada and from places in the United States as far away as Alaska, California and New Iberia, La. Wendy Dionne Gianotti came all the way from Milan. "For all the world, I never knew I had so many cousins," Joe Dionne, one of the American contingent, told about 200 Dionnes who had gathered for a seminar on family history. "Hello, y'all!"

All those Dionnes in one place created some problems. If your last name is Dionne and you live anywhere in the United States outside of Maine, you rarely get confused with anyone else. It's not like being a Jones or a Smith or a Sullivan. But when I arrived at the Avis counter in Quebec City, I had to sort through five separate Dionne reservations.

That was only the beginning. At the Motel Universel in Riviere-du-Loup, the center of the reunion, almost everything was done by first name, but even that didn't always help. When I went to register for the conference, there were five different Eugene Dionnes on the list, none of them me.

My distant cousins and new friends, John Dionne, a businessman from Grand Isle, Me., and Claire, his daughter, got it all sorted out and secured the requisite tickets and passes. It turned out that even in the family, you needed family connections. So many Dionnes showed up unexpectedly that 300 got turned away from the big Dionne banquet on Saturday night.

You would think that if we're all in the same family, we'd look alike. No way. Staring at the crowd in the lobby, people looked about as related as the folks at a VFW meeting or a union convention -- Dionnes come in every imaginable size and shape. It is, you might say, a highly varied gene pool, Antoine or no Antoine.

But Wendy Dionne Gianotti did come up with one common characteristic. "You just follow the noses," she said, staring at the crowd. "I haven't seen any small ones." I actually did find some, but you had to look hard.

The main events of the weekend besides the big banquet were a family history seminar on Saturday afternoon, organized by Raymond Dionne, a junior college teacher who lives near Quebec City; and a Sunday bus tour of famous Dionne sites.

There was also a Sunday Mass concelebrated by Bishop Gerard Dionne of New Brunswick ("I'm the bishop of the Dionnes," he told his cousinly flock) and six Fathers Dionne. We are, we were told, a very religious, very Catholic family, which wasn't surprising: The first Jean Dionne spent two years, 1667 and 1668, living with the Jesuits. I took this as an explanation of my family Jesuitical turn of mind, its tendency to argue happily for hours fine points of dogma on any subject.

Or perhaps it's Talmudic-Jesuitical. Among the interesting discoveries of the weekend was the existence of some Jewish Dionnes in the United States. Francine Dionne of Silver Spring, a specialist on Third World development, reported that there are quite a few Dionnes in Senegal. (Unfortunately, none of them came.) For good measure, I ran into an Episcopalian Dionne and a Mormon Dionne. Move over, Jesse Jackson: We Dionnes are the real Rainbow Coalition -- a French Canadian Catholic American Black Jewish Protestant family.

I also learned that while there are an estimated 25,000 Dionnes in this hemisphere, there are almost no Dionnes left in France -- the association counted only 25 families in the whole country.

This is a matter I hope the researchers at the Dionne Association pursue. But the absence of knowledge allowed for much speculation about the shortage of Dionnes in France. Norman Dionne of Arlington, Mass., wondered if maybe the Jewish Dionnes were really the original ones, and that someone converted to Catholicism somewhere along the line. On this theory, we're all migrants from Eastern Europe who just kept heading west to Canada. The factual basis for this view, Norman acknowledged, is nonexistent. But there may be a movie in it somewhere.

Dave Dionne of Springfield, Vt., opted for a simpler explanation: that where the Old World had been hostile to the Dionnes, the New World had been thoroughly hospitable. He liked this idea, since it made us a thoroughly New World family.

There was a lot of talk about the successful Dionnes -- and not much, alas, on the rogues and knaves in our past. The Dionne Association isn't big on bad news. One of my favorites among the good guys was Narcisse Euthrope Dionne, if only because of his name. There was also Jean-Baptiste Dionne who -- so legend has it -- battled bravely and successfully against the English, only to see the French cause go down on the Plains of Abraham in 1759. One of the richest Dionnes in history was Amable, who lived in the mid-1850s and purchased two seigneuries, the rough equivalent of landed peerages. More recently, there was Charles Eugene Dionne, a popular local politician who served in the Canadian Parliament for nearly two decades, retiring in 1980.

The big event of the reunion was the Saturday dinner, where 700 people crowded into a banquet hall. If you've gone to a lot of political dinners, you know the scene. But it was mind-boggling to know that about 90 percent of the people in the room shared your name.

Without doubt, the highlights of the evening were the performances of three different Dionne rock stars of the future, all three of them women. I thought of them as Tiffany Dionne, Madonna Dionne and Paula Abdul Dionne. Tiffany was 17-year-old Vicky Dionne, known onstage simply as Vicky. Nadine Dionne, 24, is more innocent than Madonna offstage, but was thoroughly tough and (if you can say this about a distant cousin) sexy onstage. Isabelle Dionne, 20, had a strong voice and brought the crowd to its feet with renditions of several pop tunes that are much loved in Quebec. Look for all three in your record stores someday.

To mix things up, John Dionne's family of six daughters and two sons performed a thoroughly wholesome set of traditional tunes, and Vincent Dionne, a classical musician by training, offered the crowd some new age numbers.

The crowds moved the next morning for the all-Dionne Mass to the church in Kamouraska that was Jean Dionne's parish 290 years ago. Then came lunch for about 700 at a hockey rink (we are Quebecois after all) and the bus tour. We saw the farm where Jean settled back in 1700 -- and it is still in the hands of the Dionne family. ("We all own a very small part of it," said John, though he didn't press his point with the Dionnes who actually do.)

There was also the rambling manor house that Amable Dionne built in the 1850s after he bought his seigneuries. It's a regular tourist attraction -- not just for Dionnes -- preserved by the local government as a symbol of the old Quebec. The bad news is that Amable's family had sold it off long ago, so none of us had any claims we could press.

The best discovery of the entire weekend was at a monument to the original settlers in the Kamouraska area. As we were told, the monument honored Jean Dionne and Charlotte Mignot, his wife. But Lucie-Anne Dionne Thomas, a lawyer from Middletown, R.I., called my attention to another plaque, honoring Maurice-Louis le Brice de Kerouack (1706-1736), the late Jack Kerouac's ancestor. The thought of my ancestors and Jack Kerouac's sitting around late at night in the Quebec countryside discussing 18th-century beat poetry did my heart good.

By the end of the reunion, the question remained: Why in the world did we all come?

For many in the American wing, the answer was simple curiosity. Nicolas Dionne, 15, of Fredonia, N.Y., said he had never met any Dionnes except his close cousins. His 8-year-old sister, Marissa, pronounced herself quite satisfied with the State of the Dionnes. "I like them," she said.

Georgette Dionne Jebb, 34, a teacher who lives outside Buffalo, said that in a world in which families are separated by distance, and sometimes by dissension, "it's very hard to get a sense of continuity."

"When you received that letter," she added, "you suddenly knew there were a lot of people out there."

Her husband, Todd Jebb, said the reunion was popular for the same reason Alex Haley's "Roots" was popular: "There's a psychological desire to know where you came from."

Father Earl Dionne of North Fond-du-Lac, Wis., saw the whole thing as a sort of ego trip for everyone, a quest for the satisfactions that come from feeling welcomed by a very large extended family.

As for me, I eschew all complex psychological explanations and will simply agree with Marissa Dionne: I liked them too.