David Modell said he and his brother, John, were at their father's side when he "died peacefully of natural causes."

"'Poppy' was a special man who was loved by his sons, his daughter-in-law Michel, and his six grandchildren," David Modell said. "Moreover, he was adored by the entire Baltimore community for his kindness and generosity. And, he loved Baltimore."

Modell was among the most important figures in the NFL as owner of the Cleveland Browns, who became the Ravens after he took the team to Baltimore in 1996 -- a move that hounded him the rest of his life.

"I believe very strongly that Art Modell is one of the most important figures in the history of the modern NFL," former NBC-TV president Dick Ebersol said. "He and Pete Rozelle developed the magic formula that married the potential of television to the game."

The NFL is asking each home team this weekend to observe a moment of silence or other appropriate gesture in memory of Modell, a league official told ESPN NFL Insider Adam Schefter on Friday.

The Ravens won their lone Super Bowl in January 2001, less than a year after Modell sold a minority interest of the team to Steve Bisciotti. In April 2004, Bisciotti completed purchase of the franchise but left Modell a 1 percent share.

During his four decades as an NFL owner, Modell helped negotiate the league's lucrative contracts with television networks, served as president of the NFL from 1967 to 1969, and chaired the negotiations for the first the collective bargaining agreement with the players in 1968.

He also was the driving force behind the 1970 contract between the NFL and ABC to televise games on Monday night.

At one time one of Cleveland's biggest civic leaders, Modell became a pariah in Ohio after he moved the team.

"I have a great legacy, tarnished somewhat by the move," he said in 1999. "The politicians and the bureaucrats saw fit to cover their own rear ends by blaming it on me."

The move was also believed to be the main reason why Modell never made it into the Pro Football Hall of Fame. He was one of 15 finalists in 2001 and a semifinalist seven times between 2004 and 2011.

"I believe Art belongs in the Hall of Fame," former New York Giants owner Wellington Mara, now deceased, said in 2002. "I don't think I know a person who has done more for the league than Modell, especially through television."

NFL commissioner Roger Goodell posted on Twitter: "Art Modell's leadership was an important part of the NFL's success during the league's explosive growth during the 1960s and beyond ... Art was a visionary who understood the critical role that mass viewing of NFL games on broadcast television could play in growing the NFL."

Goodell also appreciated Modell's sharp wit.

"Art's skills as an owner and league contributor were matched only by his great sense of humor," he tweeted. "Any conversation with Art included laughs."

Modell's Browns were among the best teams of the 1960s, led during his first few years as owner by legendary running back Jim Brown. Cleveland won the NFL championship in 1964 -- Modell's only title with the Browns -- and played in the title game in 1965, 1968 and 1969.

Modell said he lost millions of dollars operating the Browns in Cleveland and cited the state of Maryland's financial package, including construction of a $200 million stadium, as his reasons for going to Baltimore. The Ravens replaced the Baltimore Colts, who moved to Indianapolis in 1984.

"This has been a very, very tough road for my family and me," Modell said at the time of the move. "I leave my heart and part of my soul in Cleveland. But frankly, it came down to a simple proposition: I had no choice."

Ironically, the cost of the move to Baltimore left him financially strapped and left him no choice but to put in motion the chain of events that enabled Bisciotti to assume majority ownership of the franchise.

Bisciotti has since poured millions into the team, financing construction of a lavish practice facility in Owings Mills, Md. As a tribute to Modell, Bisciotti insisted that a huge oil painting of Modell be hung above the fireplace at the entrance to the complex.

Modell wasn't the kind of owner who operated his team from an office. He mingled with the players and often watched every minute of practice.

"Art talked with me every day when I played in Baltimore," former Ravens tight end Shannon Sharpe said. "He knew everything about what was going on in my life. He showed real concern. But, it wasn't just me. He knew the practice squad players' names. He treated them the same. He was out at practice when it was 100 degrees and when the December snows came. I loved playing for him."

Born June 23, 1925, in Brooklyn, N.Y., Arthur B. Modell dropped out of high school at age 15 and worked in the Brooklyn Navy Yard cleaning out the hulls of ships to help out his financially strapped family after the death of his father.

He completed high school in night class, joined the Air Force in 1943, and then enrolled in a television school after World War II. He used that education to produce one of the first regular daytime television programs before moving into the advertising business in 1954.