College football’s early-2010s conference realignment period changed the tenor of a lot of rivalries. Annual battles like Texas vs. Texas A&M and Kansas vs. Missouri were discontinued when the Aggies and Tigers moved to the SEC, but passive aggressiveness on all sides has allowed the rivalries to continue on slow simmer.

One NFL rivalry has topped that: the Colts and Patriots didn’t really become rivals until they ceased being division mates. In 2002, the Colts moved into the new AFC South — despite being south of very little — with the Jaguars, Titans, and Texans. After playing each other twice a year (not including strike-shortened years) every season since 1970, the Colts and New England Patriots have played each other in the regular season just 12 times in the 16 years since the realignment.

Two years after their separation, however, Colts-Patriots became the most important rivalry in the NFL.

Act I: Everything before Touchdown Tom

As division rivals, the Colts and Patriots were rarely good at the same time. The Patriots had their first truly awesome NFL team in 1976 (they came over from the AFL in 1970), going 11-3 and splitting the season series with the 11-win Colts. Baltimore earned the East title and got blown out by the Steelers in the playoffs; the Pats led eventual Super Bowl champion Oakland in the fourth quarter before caving.

The next year, the teams split the series again, with the 10-4 Colts finishing a game up in the East race. (This time it was their turn to lose to the Raiders in the playoffs.)

It took 10 years for the teams to again find a rhythm at the same time. The Colts finished 9-6 in the strike-shortened 1987 season and finished a game up on the Pats after again splitting the series — the Colts’ win was powered in part by a special teams play from one of the strike’s replacement players.

After yet another split, both teams finished 9-7, a game short of the playoffs, in 1988.

In 1994 and 1996, the Patriots swept the Colts, which put them two games up on their East(ish) rivals both times. In the former season, they lost to Bill Belichick’s Browns in the first round of the playoffs; in the latter season, both teams made the playoffs, with the Colts losing to the Steelers and the Pats pummeling the Steelers and Jaguars to reach their second Super Bowl.

In 1999, Peyton Manning’s first good Colts team split the series with Drew Bledsoe and the 8-8 Pats, but still won the East at 13-3 and got upset in the divisional round of the playoffs by the Titans. The Pats missed the playoffs by one game.

In basically seven instances in three decades, the teams were simultaneously noteworthy. Not great. In rivalry terms, this was more like a family reunion — you meet each year out of obligation and little more. More like a Mizzou-Iowa State than Mizzou-Kansas, if you will.

But then, with the Colts getting their act together behind Manning, the Pats selected, almost as an afterthought, a quarterback from Michigan late in the 2000 draft.

Rivalries form through some combination of geography and capital-M Moments. Enough of one can compensate for a lack of the other. In the 2000s, the Moments flowed fast and furious for these two clubs.

Act II: Tom gets in Peyton’s way

Remember back when Peyton Manning Couldn’t Win the Big Game? Ahh, incomplete narratives. From 1999-2010, the Colts won their division seven times and made the playoffs all but once — in 2001, when second-year quarterback Tom Brady led the Patriots to a shocking Super Bowl win.

By 2003, the two teams were peaking at the same time. The Colts went 12-4 with the No. 2 offense in the League, per DVOA. The Patriots went 14-2 with the No. 2 defense. The Patriots won a 38-34 shootout in November in Indianapolis’ RCA Dome, which gave them the home field advantage in the playoffs. They would play a very different game a couple of months later.

In the playoffs, the Colts scored a combined 79 points in wins over Denver and Kansas City (which had the No. 1 offense, per DVOA). But as tended to happen in rematches, Belichick’s defensive adjustments were ridiculously effective. From David Halberstam’s Belichick biography, The Education of a Coach:

In seventeen postseason possessions over two playoff games, the Colts had scored ten touchdowns; Manning himself had completed 78 percent of his passes, for eight touchdowns and no interceptions. He had been sacked only once. On game day, the Patriots dominated the Colts offense. They hammered their receivers at the line of scrimmage, playing very physical football. “It was all about being physical, physical, physical with their receivers. We wanted to hit these guys in the mouth and let them know we are here,” Rodney Harrison, the safety, said after the game. In fact, they did it with such ferocity that Bill Polian, the president of the Colts, later complained and eventually brought the issue up with the competition committee, of which he happened to be a member.

Ty Law picked off Manning three times, and the Pats sacked him four times. In the biggest ever game between these two rivals, New England broke out to a 15-0 halftime lead, then cruised home, 24-14.

The next year was exactly the same story. The Pats won in a regular-season classic (27-24 this time) to earn home-field advantage in the playoffs. And in the divisional round, they dominated an even better Colts offense (No. 1 in offensive DVOA this time) by an even larger amount, forcing three turnovers and winning 20-3 in a snow storm.

Going back to 2001, this made it six wins in a row for Brady and Belichick over Manning and the Colts.

Also, Super Bowl wins during this period: Pats 3, Colts 0.

Act III: Peyton’s revenge

From 2005-09, the Patriots went 59-21 in the regular season, furthering a level of sustained success that has proven almost impossible in the salary cap era. But aside from their unbeaten regular-season run in 2007, they played an almost secondary role in the NFL landscape because of the Colts, who went 65-15 in this span — an average record of 13-3 — and made two Super Bowls, winning one. They were so good in this period that it feels like underachievement that they only won the AFC twice.

The Colts also won five of six head-to-head matchups. A rivalry isn’t a great rivalry if it’s one-sided.

Oh man, these games were close, too. The Colts won by seven at Gillette Stadium midway through the 2006 season, which again determined home-field advantage when they met in the playoffs — a 38-34 classic in Indy — a couple of months later. They came as close to beating the Pats as anyone not named the Giants during New England’s amazing 2007 run, and then they won by three points in 2008 (when Brady was injured) and by one point in 2009.

Manning finished with just a 6-9 record against Belichick’s Pats in Indianapolis, 4-8 against Brady. But this five-year run defined this battle as a true rivalry and not just as the Patriots being the Affirmed to Manning’s Alydar.

Act IV: Dispersal

When Texas and Texas A&M played each other, it still looked right even when both teams weren’t at their best. There will still be a little bit of that feeling when the Colts and Patriots meet on Thursday night at the Gillette.

Still, a Moments-based rivalry needs Moments to survive, and there have been fewer of those since Manning left town. Beginning with 31-28 win in November 2010, the Patriots have ripped off another winning streak — this time, it’s at seven wins in a row — over the Colts. That includes three tight regular-season wins, but it also includes two playoff blowouts. Andrew Luck has led Indianapolis to three playoff berths, and the last two ended with defeats of 43-22 and 45-7 in Massachusetts.

Since Brady will probably play until he’s about 65 years old, Luck might get a few more shots at him. But there’s no better time than the present to re-kindle a rivalry.