For decades, it sat atop a glass display case, its gold surface darkened, its legendary status unknown to almost everyone who walked into I. Switt Antiques on South Eighth Street.

The Philadelphia Challenge Cup, better known as the "gold cup," was to rowing what the America's Cup is to yachting.

Any serious student of the sport knew about the cup, worshipped the names of the rowers engraved upon it, and could tell the tale of its origin in 1920 as a tribute to Olympic gold medalist Jack Kelly Sr. and of its mysterious disappearance in the 1960s.

Today, the cup is back in the hands of rowers - and one hamburger titan. During a City Hall news conference last week, they announced plans to make the cup a centerpiece of a new race during the May Aberdeen Dad Vail Regatta that will pit the world's top four single scullers of each sex against each other on the Schuylkill. A race among rowers of that ability has not happened in the United States since the 1996 Atlanta Olympics.

Organizers hope excitement around the Philadelphia Challenge Cup race will revive interest in single sculling in this country. Americans such as Kelly once dominated the sport, but no American is a champion in the event today, partly because athletes in other countries start rowing at younger ages.

"Most sports have some sort of catalyzing event, like the movie Breaking Away was for cycling, and that's how I'm looking at this," said Dan Lyons, a former Olympic rower who runs a Narberth consulting business and is organizing the Challenge Cup.

Lyons is working on the race with Jim Barker, who has coached sculling at the Undine Barge Club and the Haverford School for more than 40 years; Bill McNabb, a varsity rower at Dartmouth College who is chief executive of Vanguard, the Malvern mutual-fund company; and Scot Fisher, a professor at Jefferson Medical College.

Fisher persuaded his father-in-law, Herb Lotman, to help raise money for the Dad Vail Regatta when it nearly moved to New Jersey in 2010.

Last summer, Fisher and his children, all rowers, started urging Lotman to restore the gold cup to rowing.

"I asked them, 'What is the gold cup? Is it something you can drink from or use for beer?' and they said no," Lotman said.

Quickly, he too fell for the lore of the gold cup.

Many rowers believe the cup has its roots in an incident involving Kelly. In 1920, Kelly applied to race in the Diamond Sculls at the Henley Royal Regatta in England, the sport's most important event at the time.

But the British had rules about who could compete, and Kelly and his fellow rowers from the Vesper Boat Club in Philadelphia violated at least two.

A Henley rower could not be a "mechanic, an artisan, or a laborer," said Dan Boyne, author of a book on Kelly, the bricklayer who became the father of Princess Grace of Monaco.

"This clause was basically a way to filter out the 'nongentlemen' from events like Henley," Boyne wrote in an e-mail.

In 1905, some Vesper rowers also had taken money to pay for their travel to the race in England, which Henley organizers said violated rules requiring racers to be amateurs. It did not help that the Vesper rowers may have drunk a bit too much beer and roughed up a British hotel room.

Kelly was out, and the world heard about it. Rowing was about as popular as boxing and baseball back then, and Kelly was the sport's Babe Ruth.

He also knew how to keep his name in headlines, said his grandson Jack III, who also has rowed and who works in municipal bonds for PNC Financial Services Group Inc. in the Philadelphia region.

"My grandfather took it as a slight against his being Irish and Catholic, but he was also a good promotionalist, and he may have used that to promote the story," Kelly said.

Kelly Sr. originally said he would not race in the 1920 Olympics. After the Henley snub, he changed his mind, saying he wanted to take on the Henley winner, Jack Beresford of England.

Kelly beat Beresford in the singles final and then, with his cousin Paul Costello, won the doubles event, too. No rower has yet repeated such back-to-back Olympic wins.

Kelly won a third gold medal in the 1924 Paris Olympics.

The Schuylkill Navy, which oversees rowing events on the river, created the cup to honor Kelly and, many rowers say, to stick a finger in Henley's eye.

Over the years, rowers would either challenge each other in a race to claim the cup or win it by becoming an Olympic champion.

Winners' names were engraved on the cup. Kelly. Beresford. Vyacheslav Ivanov (five times). The last name on the cup was Don Spero's. He won in 1966.

They are names that evoke strong emotions in rowers. Vanguard's McNabb remembers studying grainy films of Spero, the American, and Ivanov, from the Soviet Union.

"For anyone who is a student of the game, it's like a who's who, so I'm reading these names and I'm getting choked up," McNabb said. "They rowed beautifully. This guy Ivanov, at the time, people just looked at him and said, 'That's the way you want to row.' "

In the 1960s, the cup disappeared, and legends grew up to explain that. Some said Ivanov had spirited it to the Soviet Union in some kind of Cold War conspiracy. Others thought a rower left it at a bar.

Still others thought it may have disappeared when former Schuylkill Navy Commodore Bill Donovan died suddenly. He had kept some of the trophies. Perhaps his family had put the cup in a storage locker when he died.

In 1996, Joan and Jack Scholl, who had lived in Philadelphia at one time but were then living in California, were visiting and looking for a place to copy some research for a family reunion when they stumbled on I. Switt Antiques, on Eighth near Sansom Street.

The windows were so dirty and cluttered that she wasn't even sure it was open, but she was on a mission. A lifelong rower, she collected antique medals. She went in to look.

The man in the store told her they didn't have any medals, but they did have an old trophy. Scholl asked to see it and immediately recognized the names.

She had rowed on the Schuylkill in the 1950s. She remembered the Australian Mervyn Wood rowing against John Kelly Jr. on the Schuylkill for the cup.

"Some stranger could have walked in and said, 'What is this piece of junk?' " Scholl said. "To us, it's not the monetary value. It's the value of the tradition in rowing."

She thought about buying it, but I. Switt wanted $30,000, which she could not afford.

She told the Schuylkill Navy about her find, and the organization sued I. Switt for the cup's return.

Switt won after a nasty, years-long battle that left the store's owners with a lot of bad feeling, said George Antoniak, who owns the antiques shop with Joan Switt Langbord. The store bought the cup legally at an estate sale, Antoniak said.

Every year, during Dad Vail, Antoniak put the cup in the store's window, an in-your-face move to the rowers who he says behaved badly during the lawsuit and over the years.

"We got a lot of prank calls, everything," Antoniak said.

In September, the group seeking to restore the Challenge Cup elected Lotman to try to buy it. He had made a fortune helping McDonald's figure out how to mass-produce frozen hamburger patties. Last summer, he sold his company, Keystone Foods, for $1.26 billion.

He also was a co-founder of golf's McDonald's LPGA Championship.

When Lotman called the store, Antoniak was apprehensive. Lotman told him to call if he was interested.

Antoniak did, and the two men spent the better part of two days negotiating a price.

"The first day I said goodbye, and I walked out because he was up in la-la-land with the price," Lotman said.

On the second day, they cut a deal. Both men agreed not to disclose the price. The cup weighs 31 ounces, so it's worth about $40,000 at current gold prices.

Lotman hopes the cup and the race will draw crowds – and maybe inspire the next Jack Kelly. He says he'll also keep his eye on the cup – and put it back in a safe when the May 14 race is over.

"This cup isn't going to leave our hands. This isn't going to be borrowed for 50 years," Lotman said. "When that cup is [at the race] site, there will be an armed guard next to it."

Contact staff writer Miriam Hill at 215-854-5520215-854-5520  or hillmb@phillynews.com.