Bill Belichick has been given the most credit for the New England Patriots‘ historic dynasty over the last two decades, and rightfully so. In 21 seasons as the head coach of the Pats, Belichick has led the franchise to six Super Bowl wins in nine appearances. But his right-hand man lurking behind the scenes might be just as responsible for New England’s success.

Ernie Adams, who’s served as the Patriots’ research director ever since Belichick took the head coaching job in 2000, has been instrumental in building and maintaining one of the greatest dynasties in the history of sports. But over the weekend, Belichick announced that the 2021 NFL draft is the last Adams will work for the team.

Who is Ernie Adams, Bill Belichick’s mysterious right-hand man?

Ask 50 people in the Patriots organization who Adams is and you might get 50 different answers. Some might say he’s the smartest football mind they’ve ever come across. Others will have no idea who you’re talking about.

Adams might be a foreign name to anyone outside the New England area, but he’s had more to do with the Patriots’ success over the last 21 years than anyone not named Belichick or Tom Brady.

But who is this mysterious man?

Adams has been Belichick’s closest confidant for more than 50 years. The two met at Phillips Academy in Andover in 1970, and they immediately bonded over their love of football. When Belichick took the Patriots’ head coaching job in 2000, he brought Adams on board as a research director. Every week, Adams digests game film of the upcoming opponent and finds weaknesses for New England to exploit.

When Malcolm Butler intercepted Russell Wilson on the goal line to ice Super Bowl 49? Adams knew what play the Seattle Seahawks liked to run out of that formation, and Butler was prepared for it. When Belichick looks to be talking to himself while he meanders up and down the sidelines on game day? It’s Adams on the other side of his headset, sitting in the press box and feeding the head coach any information he can gather.

Former Patriots offensive lineman Matt Light had the best description of Adams when he spoke to Wright Thompson of ESPN years ago.

“Ernie is a bit of a mystery to all of us,” Light said. “I’m not sure what Ernie does, but I’m sure whatever it is, he’s good at it.”

Belichick announces the 2021 NFL draft was Adams’ last with the Patriots

After the 2021 NFL draft wrapped up, Belichick announced that it will be Adams’ last one with the Patriots. As a parting gesture, the team allowed Adams to make its final draft pick of the weekend himself. He chose UCF wide receiver Tre Nixon, who is now destined for the Hall of Fame.

“Certainly, he’s been a huge part of the draft process with the New England Patriots going all the way to Coach [Chuck] Fairbanks to the Giants to Cleveland back to New England,” Belichick said in his post-draft press conference. “The acquisition of a lot of great players, all the process that goes into drafting, grading players, scouting players, setting up the grading scale, trading — really every single thing that is involved in that, Ernie’s had a seat in that role and been a part of all those things in the draft room.”

Belichick gushes over Adams’ “historic” contributions

It might be impossible to calculate Adams’ contributions to the Patriots over the last 21 years. But one man knows exactly how much he’s meant to the franchise during that span, and that’s Belichick.

“Ernie’s contributions are historic,” Belichick said. “He’s literally been involved in every single aspect of the football program at every level that you could possibly be involved in and has done an outstanding job in all of them.

“Not all coaches have the kind of involvement that Ernie’s had in the draft process throughout his career. His knowledge, experience and decisions and organization and being part of the process, the way he set it up and taught it to really all the people that have come through here … he’s really had a big hand in the foundation when it was laid in the middle 70s. It’s on a major level.”

The loss of Adams will hit the Patriots much harder than many fans can imagine.