Stuart C. Davidson, 78, a former investment banker who saw a change in D.C. liquor laws as his chance to start Clyde's of Georgetown, a fabled saloon that became a swinging and at times eccentric eatery, died Aug. 1 at a hospital in Oslo, Norway.

Mr. Davidson, a Georgetown resident, was on a trip through Scotland and Norway when he died of complications from acute myelogenous leukemia.

Besides Clyde's, which he opened in 1963, Mr. Davidson operated several other restaurants: the upscale Old Ebbitt Grill on 15th Street near the White House and 1789 Restaurant on 36th Street in Georgetown; the Tombs, the informal downstairs part of 1789; F. Scott's, an art-deco-styled supper club on 36th Street; and the Tomato Palace, a midscale Italian restaurant he started in Columbia.

The Clyde's franchise expanded from its original M Street location in Georgetown to Tysons Corner, Reston, Columbia, Chevy Chase and Alexandria. Clyde's Restaurant Group had annual gross sales of $60 million in 2000, according to a marketing official.

Reportedly the first full-sized bar in Washington since Prohibition and partly modeled after P.J. Clarke's in New York, Clyde's became a gateway to a new sort of area food establishment that featured monogrammed paraphernalia, from T-shirts to ashtrays.

Henry Allen of The Washington Post once wrote, "If it didn't create the types who flocked there, it became an instant club for them -- Mount Vernon College girls in Pappagallo shoes, McMullen blouses, Villager skirts and Liberty sweaters; Georgetown Foreign Service School types in some of the first Gucci shoes and Paul Stuart suits seen in Washington: tousled Irish Catholic kids in jeans and tweed sports coats, whose great regret in life was not being old enough to have gotten drunk with Dylan Thomas at the White Horse in Greenwich Village."

While former Post restaurant critic Phyllis Richman gave Clyde's cooking only tepid approval, she lauded the atmosphere, from a garden atrium to a handsome dark wood-and-brick bar that "makes every single guy look eligible."

Clyde's, which used to have an omelet room, also was credited with popularizing Sunday brunch in Washington.

There was also no shortage of strange, sometimes apocryphal stories about life at Clyde's.

Starting with the pickle story: When people repeatedly rejected the pickles accompanying the burgers, the staff began "notching" them to see how many times they would return to the kitchen. Some counted 10 notches.

The rowdy Dustin Hoffman story: When the actor was filming "All the President's Men," he allegedly tried to engage members of the Kennedy family in a food fight.

And the episode with the Saudi prince: His check bounced after the poor fellow overspent his allowance. He was put to work as a waiter for a week.

"They didn't have the money then that they've got now, of course," Mr. Davidson told The Post. "Oil was only selling for a buck or two a barrel."

Tales of Clyde's became as mythical as its reputed namesake, a Zelig-like character given life in pictures throughout the restaurant. "Clyde" might be the blurred image in a photo of Crimean War veterans or the unidentified man in a snapshot of a misbegotten sports team.

Clyde's called itself "An American Bar," and Mr. Davidson said it was profitable from its first day, Aug. 12, 1963. Washington liquor laws had been loosened a year earlier, permitting hard liquor to be sold at the bar for the first time since 1917. Previously, patrons had to be seated at a table to be sold liquor.

Mr. Davidson often said the premise of the business was, "It's more fun to eat in a saloon than to drink in a restaurant."

Stuart Carleton Davidson was born in Dayton, Ohio, where his maternal grandfather, Frank Patterson, was a founder of National Cash Register.

Mr. Davidson, who grew up in Washington, was a graduate of St. Albans School. He graduated from Harvard University, where he also received a master's degree in business administration. He was an Army Air Forces veteran of World War II.

According to a Post account during the war, Mr. Davidson played down his father's occupation, describing him on questionnaires simply as a "government employee" or "soldier." In fact, Howard C. Davidson was an Army Air Forces major general who commanded the 10th Air Force in the India-Burma area.

In the 1950s, young Mr. Davidson worked in investment banking in New York, Boston and Switzerland but returned to the Washington area to reevaluate his life after his first divorce. He saw his opportunity after the liquor law changed.

He had two partners over time. The first, the late James William "Billy" Bonbrest III, was bought out in the mid-1960s. John G. Laytham, a Georgetown University Foreign Service school student who started as a dishwasher at Clyde's, became the minority partner in 1968.

In 1970, Mr. Davidson bought the Old Ebbitt Grill during an auction. He originally intended to purchase the mahogany bar but wound up taking the whole establishment for $11,250. The restaurant, dating to the 1850s, had been shut down by the Internal Revenue Service for failure to pay back taxes.

Of all his holdings, Mr. Davidson once said Clyde's of Georgetown was his favorite. "This place is more fun," he told a reporter.

His avocations included kayaking.

His marriages to Polly Wheeler and Jane Poncia ended in divorce.

Survivors include his wife of 29 years, Sally Foulis Davidson of Washington; three children from his first marriage, Ellen Lindsay Davidson Shea of Brooklyn, N.Y., Olga Merck Davidson "Holly" Boszormenyi-Nagy of Washington and Boston and Stuart Patterson Davidson of San Francisco; a son from his second marriage, Alexander Johnston Davidson of Boston; three sisters, Mary Howard Davidson Swift of Washington, Julia Shaw Davidson Cheshire of Panama City, Fla., and Frances Patterson Davidson Bortz of Reading, Pa.; and seven grandchildren.

Stuart Davidson opened Clyde's on M Street in 1963 -- the first full-sized bar in Washington since Prohibition.