Oakland, Calif. ? Al Davis was a rebel with a cause — “Just win, baby” he exhorted his beloved Oakland Raiders.

And as the NFL well knows, he was also a rebel with a subpoena.

Davis, who bucked league authority time and again and won three Super Bowl titles during his half-century in professional football, died Saturday. He was 82.

The Hall of Famer died at his home in Oakland, the team said. The cause of death was not immediately disclosed.

Davis was one of the most important figures in pro football history from his role in the development of the AFL, the merger with the NFL and the success he built on the field with the Raiders.

“Al Davis’s passion for football and his influence on the game were extraordinary,” Commissioner Roger Goodell said. “He defined the Raiders and contributed to pro football at every level. The respect he commanded was evident in the way that people listened carefully every time he spoke. He is a true legend of the game whose impact and legacy will forever be part of the NFL.”

Davis was also a litigious gadfly. That was most evident during the 1980s when he went to court — and won — for the right to move his team from Oakland to Los Angeles. Even after he moved the Raiders back to the Bay Area in 1995, he sued for $1.2 billion to establish that he still owned the rights to the L.A. market.

Before that, though, he was a pivotal figure in hastening the merger between the AFL — where he served as commissioner — and the more established NFL. Davis was not initially in favor of a merger, but his aggressive pursuit of NFL players for his fledgling league and team helped bring about the eventual 1970 combination of the two leagues into what is now the most popular sport in the country.

“Al Davis was a good man, and we were friendly rivals,” Steelers chairman emeritus Dan Rooney said in a statement released by the Steelers. “He was a football man and did a lot for the game of football. I had a lot of respect for him, and he will be missed throughout the entire NFL.”

But Davis was hardly an NFL company man.

Not in the way he dressed — usually satin running suits, one white, one black, and the occasional black suit, black shirt and silver tie. Not in the way he wore his hair — slicked back with a ’50s duck-tail. Not in the way he talked — Brooklynese with Southern inflection. Not in the way he did business — on his own terms, always on his own terms.

“His contributions and expertise were inspiring at every level — coach, general manager, owner and commissioner,” Dallas owner Jerry Jones said. “There was no element of the game of professional football for which Al did not enjoy a thorough and complete level of knowledge and passion.”

Elected in 1992 to the Pro Football Hall of Fame, Davis was a trailblazer during his half-century in professional football. He hired the first black head coach of the modern era — Art Shell in 1988. He hired the first Latino coach, Tom Flores; and the first woman CEO, Amy Trask. And he was infallibly loyal to his players and officials: to be a Raider was to be a Raider for life.

People carrying flowers, flags, silver and black pompoms and even a football-shaped balloon stopped by to pay tribute on a warm, crystal clear fall day in the Bay Area. A tiny candle burned as well.

“It’s like losing a grandfather,” said Rob Ybarra of Alameda, who left a bouquet of white flowers shortly after hearing the news of Davis’ passing. “He’s such an icon. The face of the Raiders. It’s hard to put into words how much he meant to everyone.”