NEW ORLEANS -- Who owns "Who Dat?"

Some T-shirt makers are asking that question after they were hit with cease-and-desist letters from the NFL demanding that they stop selling shirts with the traditional cheer of New Orleans Saints fans.

The National Football League says the shirts infringe on a legal trademark it owns. Separately, two brothers and longtime Saints fans claim they own the phrase, which was around before the long-downtrodden team's inception in 1966.

The league said Friday it's not trying to exclude all uses of Who Dat and the fleur-de-lis logo -- just when either is used in combination with other Saints trademarks, like their fleur-de-lis logo and uniform designs.

The chant -- "Who dat say dey gonna beat dem Saints" -- is often shortened to "Who Dat" on shirts and signs and has been a mainstay at the Superdome since the 1980s. Saints fans, still jubilant after the Saints' win over the Minnesota Vikings for their first Super Bowl appearance, have voiced their dismay on radio talk shows, blogs and Web site posts.

Many say it's something that simply can't be owned.

"How can they put a trademark on something that's been around for 150 years?" said Robert Lauricella, a 50-year-old oil field sales representative. "Just because the Saints have made the Super Bowl, why does everybody have to make a buck?"

Shirts bearing the Saints cheer are big business as the team prepares for the big game against the Indianapolis Colts in Super Bowl XLIV on Feb. 7 in Miami.

Lauren Thom, owner of the Fleurty Girl T-shirt shop in New Orleans, said Thursday that she recently received a letter from the NFL demanding that she quit selling "Who Dat" shirts.

"I don't mind paying royalties," Thom said. "I just don't know who owns 'Who Dat' or whether it's in the public domain."

The beloved 'Who Dat' cheer and the NFL's claim to the legal trademark has put Saints fans in a defiant state of mind. AP Photo/Judi Bottoni

The NFL doesn't cut much slack when it believes it owns a trademark. This case is no exception.

In an e-mail, league spokesman Brian McCarthy said the NFL has sent a handful of letters in the past year asking vendors to stop selling "Who Dat" merchandise. The unlicensed shirts led fans to believe the Saints endorsed the product, he said.

"This helps protect the local businesses that are selling legitimate Saints merchandise and also the local printers that are making the licensed Saints apparel," he said.

Meanwhile, WhoDat Inc., controlled by longtime Saints fans and brothers Sal and Steve Monistere, also claims rights to the phrase.

In 1983, Steve Monistere produced the song "Who Dat Say They Gonna Beat Dem Saints" with Aaron Neville and several Saints players.

In a statement Thursday, WhoDat Inc. said that before that recording, there were no branded items with the motto. The brothers said the company has the only federal trademark for "Who Dat." Steve Monistere said he and his brother were at the Saints' first game in 1967 and have been fans through all the ups and downs -- mostly downs, of course.

Storyville shop co-owner Gabriel Harvey pulled his "Who Dat" shirts after getting letters from the NFL and WhoDat Inc.

"It seems unclear who, if anyone, owns it," Harvey said. "A lot of people believe it belongs to the city and the people."

Two members of Louisiana's congressional delegation -- Republican Sen. David Vitter and Democratic congressman Charlie Melancon -- took public umbrage at the NFL.