ENGLEWOOD – There is a reason why we kept calling it a historical defense.

A dominant defense may have produced a Super Bowl 50 title for the Denver Broncos, but history says it was foolish to expect a repeat.

Look at all the great defenses of the modern era. The 1985 Chicago Bears. The 2000 Baltimore Ravens. The 2002 Tampa Bay Buccaneers. The 2013 Seattle Seahawks. The 2015 Broncos.
Great as they were, all were one and done.

The Seahawks defense of 2013 that destroyed Peyton Manning’s high-flying Broncos in Super Bowl XLVIII nearly repeated – and their window remains open for another year or two -- but they also had a young, dynamic, franchise quarterback.

The Steel Curtain of the 1970s? Yes, but those Pittsburgh Steelers also had five Hall of Famers on offense.

To summarize: It’s possible to win a Super Bowl on defense alone, but only teams with an elite quarterback can repeat.

“It’s tough to play flawless defense for 16 weeks, 20 weeks,’’ said Broncos head coach Vance Joseph. “Something’s going to happen where someone falls down or someone gives up a big play. To do it is really special. To repeat doing that is tough to do.’’

The last team to repeat as Super Bowl champs was the 2003-04 New England Patriots, who had Tom Brady at quarterback. Before that it was the 1997-98 Broncos, whose quarterback was first-ballot Hall of Famer John Elway. Then it was the 1992-93 Dallas Cowboys (Troy Aikman a first-ballot Hall of Famer), the 1988-89 San Francisco 49ers (Joe Montana, first ballot HOF), the 1978-79 Pittsburgh Steelers (Terry Bradshaw, first ballot HOF), 1974-75 Steelers (Bradshaw), the 1972-73 Miami Dolphins (Bob Griese, HOF, fifth ballot) and 1966-67 Green Bay Packers (Bart Starr, first ballot HOF).

To repeat on repeating, only those with Hall of Fame quarterbacks have gone back-to-back.

Looking back, the defensive rise of the 2015 Broncos, and abrupt, drastic fall most resembles the 2002 Tampa Bay Bucs. Both teams had average offenses and defenses that played with a fierce attitude in winning it all. Both teams remained top 5 defenses in the following two seasons, but still came nowhere near recapturing glory.

A look at the historical, NFL defensive units of the past four decades, and how their teams fared in the two seasons after their Super Bowl championships:

1985 BEARS: 15-1, Super Bowl XX, 3 Hall of Famers (Mike Singletary, Dan Hampton, Richard Dent)

Best defense I’ve ever witnessed, a claim supported by back-to-back shutouts in NFC playoffs. This was the top NFL defense in total yards (258.4 per game), points allowed (12.4), rushing yards allowed (82.4) and it was third in sacks (64) during the regular season.

And stats didn’t measure the fear the famed 46 defense inflicted on opposing quarterbacks.

1986 Bears: 14-2, Lost first playoff game

With Vince Tobin replacing Buddy Ryan (who became Eagles head coach) as coordinator, the defense actually allowed fewer points (11.7) and total yards (258.1 per game). But quarterback Jim McMahon missed six games with three different injuries, then the Packers’ Charles Martin, in arguably the dirtiest hit in NFL history, picked up McMahon and slammed his injured right shoulder to the Soldier Field turf a good 3 seconds after the play. McMahon was done for the season.

Then coach Mike Ditka lost his locker room by starting pet Doug Flutie instead of Mike Tomczak or Steve Fuller in the Bears’ first playoff game in the second round. Flutie was awful, completing 11 of 31 for 134 yards and two interceptions in 27-13 loss to Washington.

1987 Bears: 11-4, lost first-round playoff game

Finished No. 4 in total defense and points allowed, but had a whopping 70 sacks in 15 games during a season marred by a strike and replacement-player games that officially counted in NFL annals.

With Walter Payton rushing for only 533 yards in his final season, the offense couldn’t run the ball and eat the clock – a huge factor in complementing a dominant defense.

McMahon again played in only six games due to injuries, then came back and threw three interceptions in a divisional playoff game against a Washington team that wound up destroying the Broncos, 42-10, in Super Bowl XXII.

The Bears went 12-4 in 1988 and it wasn’t until 1989, when they finished 6-10, that their great defensive run was over. Still, just one Super Bowl.

2000 RAVENS, 12-4, Super Bowl XXXV, 2 Hall of Famers Rod Woodson, Ray Lewis (when he’s elected on Feb. 3)

How’s this for a defensive staff: Marvin Lewis was the coordinator, Jack Del Rio coached linebackers and Rex Ryan and Mike Smith coached the defensive line.

Ranked No. 1 during the regular season in allowing just 247.9 yards and 10.3 points per game.
High-round disappointments-turned-journeymen Tony Banks and Trent Dilfer split the quarterback duties until the postseason when Dilfer got the job. He completed just 35 of 73 for 590 yards in four postseason games, but the Ravens won by scores of 21-3 (against the Broncos), 24-10, 16-3 and 34-7 against the New York Giants in the Super Bowl.

2001 Ravens: 10-6, won first-round playoff game, lost in second round

Defense slipped to No. 4 in total yards (277.9 per game) and No. 5 in points allowed (16.6).

Running back Jamal Lewis, who rushed for 1,364 yards as a rookie in 2000, suffered a season-ending ACL tear in training camp and missed the season.

The Ravens dumped Dilfer and signed free-agent quarterback Elvis Grbac to a then-enormous five-year, $30 million contract.

He threw more interceptions (18) than touchdowns (15) during the regular season, then threw three picks while leading his offense to only 3 points in a 27-10 playoff loss to Pittsburgh.

2002 Ravens: 7-9, missed playoffs

When Grbac didn’t accept a pay cut, he was released and even though Jamal Lewis returned for another 1,300-yard rushing season, the Ravens played with Jeff Blake and Chris Redman at quarterback and lost middle linebacker Ray Lewis for all but 5 games with a hamstring tear.

The Ravens did welcome a rookie safety named Ed Reed, who replaced the veteran Woodson, who was cut, only to lead the NFL with 8 interceptions in 2002 with Oakland.

2002 BUCCANEERS: 12-4, Super Bowl XXXVII, 2 Hall of Famers (Warren Sapp, Derrick Brooks) and potentially two more (John Lynch, Ronde Barber).

Allowed 9 points or less in seven games during the regular season, including two shutouts. Ranked No. 1 in points allowed (12.3 points), yards allowed (252.8) and interceptions (31) by considerable margins.

Matched up against Oakland’s No. 1-ranked offense and No. 1 scoring offense in the Super Bowl and intercepted league MVP Rich Gannon five times, three of which were pick sixes.

2003 Bucs: 7-9, missed playoffs

Still were No. 5 in total defense (279.1 yards per game) and No. 4 in points allowed (16.5). Had 11 fewer interceptions and seven less sacks than in 2002. Super Bowl MVP safety Dexter Jackson left for free agency and a nice contract with Arizona.

Lynch played with neck pain that required surgery after the season and led to his release.

Quarterback Brad Johnson, playing for his third team, threw 15 more interceptions in 2003 (21) than he did in 2002 (6). The offense lost star fullback Mike Alsott and No. 1 receiver Keyshawn Johnson for significant periods with injuries.

2004 Bucs: 5-11, missed playoffs

Lynch was gone to Denver, where he made four Pro Bowls in four seasons. Sapp went to Oakland, where he had two more good seasons of the four he played.

The defense still ranked No. 5 in yards (284.5 per game) and tied for 9th in points allowed (19.0).
Johnson was replaced by Brian Griese at quarterback.

2013 SEAHAWKS: 13-3, Super Bowl XLVIII, 3 potential Hall of Famers (Richard Sherman, Earl Thomas III, Bobby Wagner).

No. 1 by wide margins in total defense (273.6 yards per game) and points allowed (14.4).

Made its mark as the Legion of Boom by suffocating and intimidating the Manning-led Broncos, who were the best single-season offense of all time, by a score of 43-8 in the Super Bowl.

Unlike the other defensive-dominated Super Bowl champions, though, the Seahawks had an elite quarterback for the future. They got by with a second-year, third-round, 5-foot-11 quarterback in Russell Wilson, who was 16th in passing yards (3,357) in 2013 but also rushed for 539 yards.

Wilson only made a $536,000 salary in 2013, allowing for a balanced distribution of roster talent.

He was complemented by the strong running of Marshawn Lynch, who rushed for 1,257 yards and a league-most 12 touchdowns.

2014 Seahawks: 12-4, Lost Super Bowl XLIX

Should have repeated. Still No. 1 by significant margins in total defense (267.1 yards per game; 33.8 better than second-place Detroit) and points allowed (15.9; 1.7 points better than next-best Kansas City).

Offense improved from 18th in the league in 2013 (339.0 yards per game) to 9th in 2014 (375.8).

Suffered heartbreaking loss the New England, 28-24 in the Super Bowl as on second-and-goal from the 1 with 26 seconds remaining, coach Pete Carroll called for a pass and Wilson was intercepted at the goal line by Malcolm Butler.

2015 Seahawks: 10-6, won first-round playoff game, lost in second round.

Finished No. 2 in total defense (291.8 yards per game) to the Broncos and No. 1 in points allowed (17.3) to edge Denver.

This team was increasingly belonging to Wilson as the Seahawks ranked No. 4 in total offense (378.6 yards) and points (26.4) even though Marshawn Lynch missed the final nine games with a sports hernia, and then sat out the next season.

The Seahawks went 10-5-1 and won a playoff game in 2016 and are 8-4 so far this year. They have remained mostly a top 5 defense since their great 2013 Super Bowl run, although they are a top 10 defense this year.

But the reason why their defensive window is still open is because they are much more balanced team with Wilson at quarterback.

2015 BRONCOS: 12-4, Super Bowl 50, 3 potential Hall of Famers (DeMarcus Ware, Von Miller, Aqib Talib).

No. 1 in total defense (283.1 yards per game) and No. 2 in points allowed (18.5) during the regular season. Was also No. 1 in pass defense (199.6 yards), No. 1 in sacks (52) and No. 3 in rush defense (83.6 yards).

Rose up in the postseason for a combined 14 sacks in three games against the likes of Ben Roethlisberger, Tom Brady and league MVP Cam Newton.

Miller and Ware were unblockable edge rushers during the postseason while the No Fly Zone of Talib, Chris Harris Jr., Bradley Roby, T.J. Ward and Darian Stewart smothered opposing receivers with man-to-man coverage.

The Broncos also got a strong inside pass rush from 3-4 defensive ends Malik Jackson and Derek Wolfe and elder statesman defensive coordinator Wade Phillips created a system of organized chaos where it appeared six were pass rushing and seven were covering.

The offense only ranked 16th in total yards and 19th in scoring as the 39-year-old Manning was hobbled in his final season. But Manning came through with a clutch, fourth quarter drive against Pittsburgh in the first playoff win, then hit tight end Owen Daniels for two early touchdown passes in a 20-18 AFC Championship win against the Patriots.

Manning didn’t play all that well in the Super Bowl but he did start each half with field goal drives. And he didn’t need a peak performance with Miller creating two touchdowns off strip sacks of Newton for a 24-10 win.

2016 Broncos: 9-7, missed playoffs

The defense still ranked No. 4 in yards and No. 4 in points allowed but it wasn’t quite as fearsome as Ware struggled through injuries and Jackson left for Jacksonville through free agency.

But the two biggest blows were Manning’s retirement and head coach Gary Kubiak falling ill in the hours after game 5.

Trevor Siemian filled in admirably as a seventh-round quarterback from Northwestern, but then he suffered a significant left shoulder injury in the fourth game of the Broncos’ 4-0 start.

The offense slid precipitously late in the season, leading to a locker room divide where the defense started pointing fingers.

2017 Broncos: 3-9, will miss playoffs

Kubiak resigned for medical reasons. The defense lost coordinator Phillips, whose contract was allowed to expire, and Ware, who was forced to retire because of a chronic back issue. Then Ward was released prior to the season, leading to social media protests from several defensive players.

The defense still ranks No. 5 in yards allowed (295.6 per game) but it is No. 31 in points allowed (26.3) in large part because the offense has surrendered 27 turnovers that have led to either directly defensive points or indirectly through short fields.

The quarterback play deteriorated with new head coach Joseph using Siemian, Brock Osweiler and Paxton Lynch, a first-round draft pick in 2016 who didn’t come along as quickly as hoped.

As the Broncos play the New York Jets this Sunday, a season-ending neck injury to Wolfe leaves just six starters from their great Super Bowl 50 defense: Miller, Talib, Harris, Stewart, Roby and linebacker Brandon Marshall.