As Scott Alberts tore through the clutter in the trunk of his compact car, he began to unearth a 19th-century baseball museum.

The round, white metal plates he extracted served as pitching mound and home plate in the days when handlebar mustaches such as Alberts' were in vogue. The "lemon peel" ball was curiously stitched but slightly softer than today's models. The woolen uniform - long, dark pants, a small-brimmed jeff cap, and a long-sleeved top whose buttoned breastplate was adorned with a large italicized "A" - looked unbearably stifling in the 90-degree heat.

"I know there's a bat in here somewhere," said Alberts, 32, an Upper Darby resident who works in the business office at the University of Pennsylvania's medical school, as he pushed aside a spare tire, a folding chair, and considerable paper.

Alberts' hunt was analogous to the quest that has become his life's passion - an ongoing search for authentic information on baseball's earliest rules, equipment, and customs.

The interest began in 2010 and led him to cofound the Athletic Base Ball Club. That team, which plays like-minded foes from several nearby states, is a revived version of the team that brought Philadelphia early baseball glory in the second half of the 1800s.

"I've been able to combine three great loves," he said. "The performing arts - because there's a certain aspect where you're playing a character, dressed up like we do - primary-source history research, and sports."

He and his two dozen Athletics compete against other vintage "base ball" teams in the Mid-Atlantic region. They use rules from 1864 and bats, balls, bases, and uniforms constructed to resemble the originals.

A history major, Alberts won't rely solely on anecdotal evidence or the mythology surrounding the game's shadowy origins. "We are really focused on sourcing," he said.

His curiosity about the era when baseball was emerging as America's game grew out of his devotion to the Phillies. Curious about where the team played before Baker Bowl, he began to research online, eventually stumbling upon the old Athletics.

Founded in 1859, that club would later play in the amateur National Association, then won the first pennant when that league went professional in 1871.

"I thought, 'Here's a team I don't know anything about,' " he said. " 'Here's a league I don't know anything about.' I was totally ignorant of 19th- century baseball except for the fact that they played it.

"When I came across references to the first guy to wear a glove or the first pitcher's mound, I just thought it would be a great idea to get 18 guys together with a case of beer and play in the park one day."

Alberts was convinced his was a unique concept. A week later, his mother brought him an article from a Maryland newspaper about a game between two vintage teams there.

"So I looked up online to find out where the Philadelphia team was," he said. "When I saw there wasn't one, my civic pride was offended. As much of a baseball town as we are, as important to the history of baseball as we are, as important as history is to our civic identity, how did this not already happen?"

Eventually, with the help of brothers Eric and Ryan Berley, who own the Franklin Fountain ice cream parlor in Old City, he found enough people with similar interests to field a team and challenge other clubs, many of whom play by different sets of rules from baseball's chaotic first decades.

These Athletics pitch underhanded from a box rather than a raised mound. Though the bases are 90 feet apart, many of the 1864 rules seem so quirky a century and a half later that the resulting game sometimes resembles cricket more than baseball.

"The game that has evolved is ultimately a better one, but the old game is interesting too, and that's why we enjoy it," said Alberts. "It's similar enough to be familiar but different enough to be a novelty. It's a unique challenge and much more interesting cerebrally than playing softball."

There are no gloves. The bats can be only 21/2 inches around and, unless someone can find an early reference to maple, must be either ash, poplar, or oak.

Their uniforms were based on what they saw in wood-cut engravings from Harper's Weekly and read about in  books. The more research Alberts did, the more intrigued he became.

"In 1867, 40,000 showed up for a game here at, I think, Camac Woods [a field near the present-day site of Temple University]," he said. "That was 5 percent of the city's population."

Alberts' Athletics have traveled as far as Queens, often playing doubleheaders in which their rules are used for one game and the opponents' for the other. They went winless in their inaugural season but have won a few this year, though victories, he said, aren't the point.

"On one level, our ultimate goal is to create a divisional structure nationwide for vintage base ball," he said. "But that's way down the road. On another level we joke that we're a revolution designed as a baseball team. We're trying to re-create a sense of community.

"There's a certain nostalgia for innocence that goes with what we're doing that I think is wrong-headed. It used to be in this city that there were neighborhoods where everyone worked at the same factories, drank at the same bars. Some still have that, and it's beautiful. But for those of us who don't, we're looking to re-create it, and this is a part of that."

"It's less of a movement," he said, "than kind of the zeitgeist for our era. Let's create something as opposed to just consuming."