ESPN celebrates the 100th anniversary of Vince Lombardi's birth with the "Greatest Coaches in NFL History" series, saluting the finest innovators, motivators, tacticians, teachers and champions ever to stalk the sidelines. Follow along as we reveal our list of the top 20 coaches of all time and document the lineage of the league's most influential coaching trees.

Any discussion of the most important figures in NFL history has to include George Halas. The longtime player/coach/owner of the Chicago Bears was there from the league's very beginning, and his impact on the league is undeniable.

When "Papa Bear" was done coaching for good after the 1967 season, his 324 total victories were far and away the most in history. That record stood for 27 years until Don Shula surpassed it in 1993. It's safe to say Halas' mark of 40 seasons as a head coach, seven more than anybody else, will never be broken. Under Halas' coaching, the Bears finished with a losing record the same number of times they won a championship -- six. And throughout his coaching tenure, he was one of the most influential owners as the league evolved from its humble beginnings.

Halas played football, baseball and basketball at the University of Illinois, and after his junior year he enlisted in the Navy during World War I. While stationed at Naval Station Great Lakes in the Chicago area, he helped organize football and basketball teams. After the war, he briefly played baseball for the New York Yankees during the 1919 season.

In 1920, he was hired by the Staley Starch Works in Decatur, Ill., to work and organize the company's football and baseball teams. Representing the Decatur Staleys, Halas attended a meeting in Canton, Ohio, that led to the creation of the American Professional Football Association, which would change its name to the National Football League in 1922.

With Halas as a player and coach, the Staleys finished second in the 14-team APFA's inaugural 1920 season. The owner of Staley Starch Works encouraged Halas to move the team to Chicago, and it was there in 1921 that the Staleys won Halas' first league championship. In 1922, Halas changed his team's name to the Bears as a tribute to the Chicago Cubs, who were letting the football team share Wrigley Field.

Halas played, coached and ran the Bears' business operations through the 1928 season. He remained on as co-owner and gained full control of the team in 1932. He returned to the sideline as head coach in 1933, starting a 10-year stretch that resulted in three more championships, including the record 73-0 destruction of the Washington Redskins in the 1940 title game.

After the Bears won the 1941 championship, Halas re-enlisted in the Navy following the attack on Pearl Harbor. While he was in the South Pacific organizing entertainment for the troops, the Bears won the 1943 championship. Halas returned in 1946 and won his fifth championship that season.

Over the next nine seasons, the Bears reached the playoffs just once, and Halas again stepped away from coaching after the 1955 season. But he couldn't stay away and returned in 1958 for his final 10-season stretch. In 1963, he was inducted as a member of the Pro Football Hall of Fame's first class. Later that year, he won his sixth championship.

After he was done coaching, Halas maintained an active role with the organization until his death in 1983. In 1984, the NFC championship trophy was named after Halas. The Bears still wear his initials on their uniform sleeves.

--Kevin Stone

HALAS THROUGH THE EYES OF A PLAYER: MIKE DITKA

He's the founder of the National Football League, no matter how you look at it. Guys like George Halas and Art Rooney and Tim Mara, they started out and persevered; they robbed Peter to pay Paul and they made the NFL what it was. You don't have a game of football if you don't have those pioneers. There were a lot of lean years.

Coach Halas had a cleaning business on the side to offset the losses. When I was drafted by the Bears, I was the fifth overall pick in the first round. So I went to Chicago to meet Mr. Halas. We sat down -- it was just him and me and a wooden desk. He said, "We're going to play you at tight end."

I didn't even know what a tight end was; nobody had written that definition. I thought I might be a linebacker because I played a lot of defense at Pittsburgh. He said, "We're going to pay you $12,000 and give you a $6,000 signing bonus." I said, "Well, that's fine." That was a lot of money compared to what my dad made working in the mill. So I had a great year, made Rookie of the Year, All-Pro, caught a lot of passes.

So at the end of the year, since they didn't have multiyear contracts back then, I went to talk to Mr. Halas again. He said, "I'm going to give you a raise, to $14,000." I said, "Coach that doesn't make sense. I made $18,000 last year. I'm not getting a raise, I'm getting a cut. I won't sign for a penny less than $18,000."

As soon as I said that he opened the drawer and pulled out a contract -- for $18,000. And I signed it. You weren't going to win an argument with George Halas, believe me. When you get paid to play the game you love, it's like stealing.

It was the same thing when he signed me as the head coach. We were sitting at the kitchen table in his apartment and he said, "We'll pay you this and give you a three-year contract." It wasn't about the money, it was about the opportunity. It's the Halas Bears, and it always will be. I'm proud to say I'm a part of that history.

-- Former Bears tight end, coach and Hall of Famer Mike Ditka, as told to Greg Garber

ESPN "Greatest Coaches in NFL History" voting panel: Chris Berman, Jeffri Chadiha, John Clayton, Colin Cowherd, Mike Ditka, Gregg Easterbrook, Herm Edwards, David Fleming, Ashley Fox, Greg Garber, Mike Golic, Suzy Kolber, Eric Mangini, Chris Mortensen, Sal Paolantonio, Bill Polian, Rick Reilly, Mike Sando, Adam Schefter, Ed Werder, Seth Wickersham, Trey Wingo.