They took an arduous path to the franchise’s 18th title, only for it to seem easy at the end. With a 106-88 victory over the Dallas Mavericks that was in hand by halftime, the Celtics earned a Monday night stroll to the TD Garden podium. They had learned all the lessons, felt all the pain, conquered all the doubt. They were meant to clinch on this night, 16 years to the day after their last championship. Their franchise players, Tatum and Brown, had been patient enough.

They had spent seven years together, chasing a trophy, the only thing that could verify them as great Celtics. They labored for 107 postseason games, the most of any star duo before winning a championship. They watched the organization cycle through big-name veterans who were supposed to lead them while they were young — Isaiah Thomas, Kyrie Irving, Gordon Hayward, Kemba Walker — and they had to adjust their games through the shuffle of three head coaches.

As NBA players, Taum and Brown were born into the success, privilege and burden of playing for the Celtics. They’ve been ring-shopping since they entered the league. In 2016, Boston drafted Brown, and in his rookie season, the team finished 53-29 and advanced to the Eastern Conference finals. In 2017, Boston drafted Tatum, and the team proceeded to win 55 games and return to the conference finals. It was a blessing to win so young. But it also guaranteed playoff heartbreak for the tandem, both of whom were drafted No. 3 overall.

“Normally, when you’re a top-five draft pick, you go to a lottery team that’s rebuilding,” Tatum said. “I was in a unique situation from the rest of the guys in my draft class in that the Celtics were the No. 1 seed in the East. We were competing for a championship ever since I got here.” Brown and Tatum didn’t have to endure seven-game losing streaks and 30-win seasons while they developed. Then again, they didn’t get to hone their craft in the comfort of relative privacy, away from the expectations and scrutiny. Instead, every setback was a referendum on their level of stardom, their trust in their teammates and in each other and their competence as winning players.

“I think we learned,” Brown said. “I think we learned from all of our mistakes. All of our adversity has made us stronger, made us tougher.”

While Tatum has been the more celebrated star, this postseason run belonged to Brown. After Boston completed a five-game series victory, Brown was named the Finals MVP. He was also MVP of the Eastern Conference finals. During this entire run, Brown was a two-way menace, impacting the game with his energy and his skill. Yet for as much as he likes recognition, he craved team success above all. By making sacrifices and playing team basketball, the individual accolades came naturally. There is no need to wonder whether he surpassed Tatum. They did it together, finally. They did it with their teammates. The Celtics were connected.

“We’ve been through a lot — the losses, the expectations,” Brown said of his relationship with Tatum. “The media have said all different types of things: We can’t play together, and we’re never going to win. We heard it all. But we just blocked it out, and we just kept going. I trusted him. He trusted me.”

To be called champions, to satisfy the exacting Celtics standard, both stars evolved into functional playmakers. Both committed to playing a cerebral game, flowing with the read-and-react wrinkles in Coach Joe Mazzulla’s offensive system and competing with focus and discipline on defense.

In the past eight years, the Celtics have made six deep playoff runs. Brown has been on the roster for all of them. During the seven years he has shared with Tatum, the players had multiple roles. The Celtics had planned to win a title while they were young complementary players, but they had neither the right combination of veteran stars nor good fortune. So Brown and Tatum tried to run through walls. They won plenty, but until Monday night, it wasn’t enough.

“It’s been a long journey,” Tatum said on the court afterward, trembling.

He shook his head and repeated, “It’s been a long journey.”

It wasn’t as long as the journey of teammate Al Horford, a champion in his 17th season. His maturity and leadership have meant much to the Celtics. When striving for something difficult and experiencing criticism, it helps to have the perspective of a 38-year-old potential Hall of Famer. It’s been a long journey, but Tatum is just 26. Brown is 27. They still have plenty of prime years left. After a dominant regular season and playoffs that saw the Celtics go 80-21 overall, the Celtics are built to compete for more championships.

Jrue Holiday and Derrick White, the potent guard tandem, will be back. Kristaps Porzingis didn’t even see much playoff action because of injury. In this era of parity, the Celtics are the sixth different champion in the past six years. But if they can stay hungry, they have a realistic opportunity to repeat.

But the repeat talk can wait. They need to revel for a long while. They’ve earned it.

Tatum lifted his son, Deuce, high above his head and shared a long hug. What seemed like 16 years’ worth of confetti rained on them. It was a moment that reminded you that Tatum, despite his age, is a grown man. Now that he has cracked the championship code, perhaps he can fully settle into himself.

“He told me I was the best in the world,” Tatum said when asked about his chat with his son. “I told him, ‘You’re damn right I am.’”

The title of “champion” changes everything. Before the playoffs, Dirk Nowitzki shared with me a story about winning his only championship in 2011. He remembered the joyous feeling of going the All-Star Game the next season. He had bragging rights. He had all-time status, delivering the Mavericks their first title. It took him 13 seasons.

“To me, that was the most gratifying and satisfying thing I’ve done in the league or almost in my life, really,” Nowitzki said. “Before, it’s like, ‘Oh, man. He’s a good player, but he hasn’t won. He’s a good player, but he hasn’t won.’ And once I won it, I don’t know. I had a different swag about me. Once I went to the All-Star Game after the championship, I was looking different. It was like, ‘Oh, there he is.’ All of a sudden, it gave me a different sense of pride and confidence. Hey, I belong here, really. I delivered something that not everybody can do.”

We’re amid a period in which superstars are graduating to legends. Last season, Nikola Jokic did it with the Denver Nuggets. Three years ago, Giannis Antetokounmpo did it with the Milwaukee Bucks. Neither Tatum nor Brown have the regular season MVP honors to compete with those résumés. But the assumption that they’re significantly lesser players might need to be re-litigated now. There is a gap. It’s not as wide as it was at the start of June.

When a reporter called the title a “career-defining accomplishment,” Tatum declared, “Say that again.”

The words rolled off the reporter’s tongue once more.

“Please say that again,” Tatum responded.

He can make that request for the entire offseason. The hardship is over. The celebration has only begun.

“It’s been a long time coming,” Tatum said, “and damn it was worth it.”