Thousands will file into Consol Energy Center to see Pittsburgh’s first Ultimate Fighting Championship event Sunday, but the history of mixed martial arts can be traced back 31 years to a Holiday Inn in New Kensington.

The Heinz History Center unveiled an exhibit Tuesday, honoring what is believed to be the first sanctioned MMA fight in American history. The idea was the brainchild of Pittsburgh fight promoters Bill Viola and Frank Caliguri, and the first match was March 20, 1980, between Mike Murray of Vandergrift and Dave Jones of North Huntingdon.

Viola said the two came up with the idea over dinner at a local Denny’s. While advertising kickboxing fights in local bars, both said they heard challenges from people who claimed to be tougher than the fighters they were promoting. Caliguri said the two decided to try something new by advertising an open competition combining all forms of martial arts, which they called the “Tough Guy Championships.”

“If they’re a wrestler, let them wrestle. If they’re a kickboxer, let them kickbox. Whatever they want to do,” Caliguri said.

The two drafted an 11-page document combining rules from various martial art disciplines, from boxing to Brazilian jiu jitsu. Viola said he took a year off from his job teaching science at Allegheny High School to promote and organize the event.

“If it’s successful you’re a genius, and if it’s not you’re an idiot,” he said.

The fights took place over three nights at the New Kensington Holiday Inn. The first pitted Murray, a boxer, against Jones, a kickboxer. Jones won when Murray’s corner stopped the fight with a few seconds to go.

“He was a better fighter that night,” Murray said.

Viola said the first event was an immediate success, filling the hotel to its capacity.

“We were totally sold out. You couldn’t get into the place,” he said.

The two immediately hatched plans to bring their new sport across the country.

Viola and Caliguri, though, may have been ahead of their time. In 1983, the Pennsylvania state legislature passed a law effectively banning the sport.

“It was horrible,” Viola said. “They cut us off at the knees.”

The state lifted its ban on MMA in 2009, as the sport had started to gain mainstream acceptance, primarily through UFC’s success. Jones said the rules today are similar to the ones he and Murray fought under, but that the fighters in modern MMA are much more polished than the early “tough guys.”

“It’s evolved into something so much more technical,” Jones said. “It’s amazing to watch these guys fight now.”

Viola, Caliguri, Murray and Jones were invited to Saturday’s weigh-in for this weekend’s UFC event. Murray said the group hopes to meet UFC president Dana White in an attempt to unite the past and present of American MMA.

“We were so far ahead of our time,” Viola said. “No one understood what we were doing, but the general population loved it.”