RIP Buddy Ryan.

Never forget the level at which men will compete when they LOVE their leader! (the '86 Super Bowl Bears, and Buddy, taught me that...)

In 1978, George Halas brought in Ryan as defensive coordinator. With the Bears, Ryan created the 46 defense, but it wasn't until 1985 that the scheme was perfected. This was due in large part because of Mike Singletary's ability to single-handedly dominate the middle of the field.  

Then Bears head coach Neill Armstrong was fired in 1982. The defensive players lobbied Bears owner George Halas to let Ryan take over, or pleaded for the owner to retain Ryan as defensive coordinator.  

Mike Ditka was hired as the head coach. Ryan and Ditka feuded openly, though Ditka delegated the defense to Buddy and left him in charge. 

Ditka challenged Ryan to a fight during halftime of the Bears' 1985 matchup versus the Miami Dolphins, with the team at 12–0 and trailing 31–10 in a nationally televised Monday Night Football broadcast. The guys on the team had to separate them—the offense getting Ditka away from Ryan and defensive guys holding Buddy. The Bears went on to lose the game 38-24, which was their only loss of the season.  

However the team would go on to Super Bowl XX where they would dominate the New England Patriots 46–10. The Bears defense carried Ryan off the field on their shoulders ...right behind Mike Ditka, who was also being carried off the field.

Defense, defense, defense...
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ADDED:  Learn something new every day...  I knew about the Purple People Eaters.  Did not know Buddy Ryan was behind that too:

In the mid-1970s Ryan served as defensive line coach for the Minnesota Vikings where he was integral in directing the team's dominating defense. The defensive unit known as the "Purple People Eaters", was heralded for the defensive line's ability to punish rivals. Their motto was to "meet at the quarterback." This unit helped the Vikings to post-season appearances from 1973 to 1978, including three appearances in the Super Bowl - two of those seasons with Ryan as defensive line coach.