The boat ride—taken by Paul Pierce, Kevin Garnett and Ray Allen, with coach Doc Rivers in September—symbolized their ultimate goal: a parade through the streets of Boston, ending on the Charles River.
The Rome trip signified an all-important bonding experience for the newly formed Big 3.
Ubuntu, invoked by Rivers in training camp, defined their all-for-one ethos: I am because we are.
The fairy-tale season unfolded just as poetically: an 8-0 start. Twenty-nine wins in their first 32 games. Sixty-six wins for the season. A six-game trouncing of the Los Angeles Lakers in June. A glorious splash on the Charles River.
"It was meant to be," a smiling Pierce told Bleacher Report recently. "It was just like the pieces of the puzzle fit perfectly."
The Celtics made it all look so easy—a harmonic blend of talent and selflessness and ferocious defense. They set the standard for the modern Big 3, and set off a wave of imitators.
Miami formed its own Big 3, and seized a pair of titles.
New York tried, and failed miserably.
The Lakers tried, and failed spectacularly.
The Brooklyn Nets tried, and created a perfectly ordinary (albeit very expensive) team.
Now Cleveland is grinding through the early stages of its own superstar experiment, with LeBron James joining Kyrie Irving and Kevin Love in the latest Big 3 to take the stage.
It has not gone well.
The Cavaliers are 6-7, having already lost as many games in November as the Celtics' Big 3 did in their first 41 games. This is the worst start for a James-led team since 2003, his rookie season.
Love is lost, Irving is out of sorts and James is bewildered.
On Saturday, James called his team "very fragile." On Monday, he took the self-loathing route and declared, "I stink." Hours later, James scored 29 points in a nerve-soothing 106-74 rout of the Orlando Magic.
Things will probably get better for the Cavaliers. They have a four-time MVP, two capable All-Stars and some useful young players. The James-led Big 3 in Miami struggled initially too, going 9-8 to start the 2010-11 season before marching to the NBA Finals.
Then again, things might not get better at all. And even if they do, the Cavaliers might prove to be merely good, not great or legendary or title-worthy.
Here's the inconvenient truth about the Big 3 model: Not all superteams are created equal. Not all superstars are compatible. Role players matter. Coaching matters. Personalities matter. Talent alone is never enough.
"I always say it comes down to cooperation," Rivers said. "If they want to cooperate with each other, it usually works out."
From the start, the Cavaliers' stars have said all the right things about sacrifice and cooperation. Platitudes come easily. Actually giving up shots and control for the greater good is much tougher, especially when there are egos and multimillion-dollar contracts involved.
"I tell people all the time: It's easy to say the word 'sacrifice,' " said Cavaliers forward Mike Miller, who spent three seasons with James, Dwyane Wade and Chris Bosh in Miami. "But to sacrifice, whether it's playing time, shots, things like that, without knowing the outcome, it's scary. And that's what you're asking players to do here in Cleveland again. You got young, talented players that are asked to sacrifice without knowing what the outcome could be. If you don't win a championship, is it worth it?"
Miller, who won two titles in Miami, hastened to add, "Guys that have been through it and won it are here to tell you that it is worth it."
Depending on who is doing the analyzing, the Cavaliers either need more passing from Irving, more post-up chances for Love, more leadership from James or probably all of the above. That still might not be enough to turn the Cavaliers into title contenders in Year 1.
Fans and pundits were spoiled, indeed deluded, by how quickly and seemingly effortlessly the Celtics went from chemistry experiment to champions in 2007-08. The Pierce-Garnett-Allen Celtics are the modern-day standard—the Michael Jordan of Big 3s. And, as with Jordan, all comparisons are inherently flawed and unfair. But comparisons in this case are inevitable and necessary.
The beauty of the Celtics' Big 3 was the seamless fit among the three stars. There was no awkward overlap in styles or roles. Pierce provided the scoring punch and the one-on-one skills. Allen provided the three-point shooting. Garnett provided the post-up threat and the defensive tenacity—indeed, served as the linchpin to Boston's entire defensive scheme.
"We all were different, but we all complemented each other," Pierce said. "The next thing you know, the chemistry and everything is perfect."
To be clear, significant sacrifice was necessary. Pierce, Allen and Garnett had all been No. 1 scoring options before uniting. Each of them gave up shots and points and individual glory. But each man had entered his early 30s by that point, and had accrued the wisdom that comes with age.
As Pierce put it, "We were all at a point in our career where we won a lot of games, never won a championship, won a lot of statistical (honors), All-Star games, Kevin had an MVP. It was like, what was left? We all wanted to win a championship."
The Cavaliers can claim none of these qualities. Irving is just 22 years old, and Love 26. Neither one has been to the playoffs, nor even been part of a winning team. Stars at Irving's age are generally gunning for scoring titles. Self-sacrifice is a harder sell.
There is nothing seamless in the Cavaliers' three-way partnership. All three stars are scorers, with overlapping skill sets. Irving needs the ball in his hands to be effective, but that role is now filled by James. There is no Garnett in this group, no defensive maestro to fill the gaps and hold everyone else accountable.
"The best pick-and-roll defense player that I've ever played with," Pierce said of Garnett. "Because he covered for a lot of the mistakes I made, a lot of mistakes [Rajon] Rondo and Ray made."
Garnett set the tone and the standard, and the rest of the Celtics followed.
"He commanded that respect," Pierce said. "And then on nights when you're getting torched, or you're not in the right spot, he's going to let you know."
Who serves that role on the Cavaliers? Irving and Love are notoriously poor defenders. James has been an elite defender in his career, but that dedication noticeably slipped last season and remains in question.
"There's no defensive commitment," Karl, the former Denver Nuggets coach, said of the Cavaliers. "Even if they get the commitment, they right now don't have talented defensive players. They don't have shot blockers, they don't have ball pressure. Other than LeBron, they don't have guys that make defensive plays."
Beyond the Hall of Fame talent, the complementary skill sets and the maturity, the Celtics' Big 3 had another massive advantage: a fourth star. Rondo began that season as a relative unknown, but he blossomed into an All-Star point guard, one of the best passers and defenders at his position.
The Celtics' fifth starter, Kendrick Perkins, was a beefy interior defender and a devastating screener. Their bench was packed with veterans—P.J. Brown, Sam Cassell, Eddie House, James Posey—and a promising young perimeter defender named Tony Allen.
Miami, too, was soundly constructed. James and Wade had similar skill sets, but it helped that both men were effective as both scorers and playmakers. It also helped that they were friends, making the transition and the sacrifice smoother.
Wade, Bosh and James were all willing and proven defenders. And all three had led their teams to the playoffs before joining forces. Wade had won a championship. James had been to the Finals. There was no shortage of perspective among them.
And they, too, were supported by a cast of savvy veterans: Miller, House, Udonis Haslem, Mike Bibby, Zydrunas Ilgauskas, James Jones. And, by their second season, Shane Battier.
"Chemistry is everything," Pierce said. "You can't overlook the added pieces. The stars are going to be the guys every night, but it's always going to be the role players that complete your team."
Although Erik Spoelstra was young for a head coach, he had been on the job for two seasons and had been with the Heat for years. He had an established rapport and trust with Wade, which helped bridge the relationship with James.
In Boston, Rivers had a long NBA track record, a longstanding relationship with Pierce and instant credibility with Garnett and Allen.
Cleveland is being coached by David Blatt, who built a brilliant reputation in the European leagues but had never coached in the NBA until now. He is still building relationships and trust while trying to adjust to the NBA game.
"I think Blatt is struggling a bit," said one veteran NBA coach. "The offense is not very imaginative. Spoelstra did good job of blending guys, creating ways to get guys isolated. I don't see that right now. They're going through the motions of an offense that isn't clicking."
The coach, who did not want to be named while critiquing a rival, said Blatt's offense relied on "a lot of European stuff that isn't going to work" in the NBA. "It's too simple. I just don't think he hits the right buttons.
"Their talent is taking over and will win some games," the coach said. "But going against elite teams, that's not going to work."
Then there are questions about the Cavaliers' supporting cast. Dion Waiters has chafed at taking a lesser role. Their bench is thin. Five of their top nine rotation players are 24 or younger, and youth rarely wins championships. They are lacking mobile big men, or rangy perimeter defenders. And NBA teams rarely win the title without a top-10 defense.
If the Cavs fail with this Big 3, they will not be the first.
The Knicks once had visions of their own Big 3, having acquired Amar'e Stoudemire and Carmelo Anthony, with whispers that Chris Paul would be next. When Paul proved unobtainable, the Knicks grabbed Tyson Chandler, adding an elite defensive big man to the scoring tandem of Stoudemire and Anthony.
"I thought we had the potential to be one of the best front lines that this game has seen in a long time," Chandler told Bleacher Report. "I thought with how dynamic Amar'e and Melo were on the offensive end, and the athleticism that they provided, and me being the (defensive) anchor to it all, I felt like this could be incredible."
But Anthony and Stoudemire were both volume scorers who needed the ball, and in similar spots on the floor. Chandler and Stoudemire had overlapping skill sets as pick-and-roll finishers. None of the three were playmakers. Only Chandler was known for defense. And Stoudemire couldn't stay healthy.
Those Knicks were at their best in 2012-13, when Stoudemire was injured and Anthony replaced him as the starting power forward. As it turned out, they were better with just two stars.
The Lakers in 2012 took the concept a step further, acquiring Dwight Howard and Steve Nash to join Kobe Bryant and Pau Gasol for a Big 4. But Bryant and Howard didn't particularly like one another, Nash couldn't stay healthy and coach Mike D'Antoni never could make the pieces mesh. The Lakers were swept in the first round of the playoffs, and Howard promptly bolted for Houston.
"It doesn't matter how much talent you put on one team, as you saw with the Lakers team with Dwight and Kobe and those guys," Pierce said. "A lot of them didn't complement each other. They were just stars."
It might be a few months before we know the true character of this Cavaliers team.
Irving was the undisputed center of the Cavs' universe for his first three seasons, averaging 20 points per game while handling the bulk of the playmaking duties. The offense was always in his hands.
Love occupied a similar place in the Minnesota Timberwolves' universe, albeit from the frontcourt.
James is the consummate teammate, a gifted passer and conscientious soul, but he is best with the ball in his hands, which means dramatic role changes for everyone else. They are still adjusting.
Love is taking nearly six fewer shots per game compared to last season, and his scoring has dipped to 16.2 points per game, from 26.1.
"Kevin Love probably needs more touches," Karl said. "He needs to be a higher priority of the offense."
Irving has been notably stingy with his passing and is prone to overdribbling—an early reminder that sacrifice is easy in concept, difficult in execution.
"They've got too much offense, with not enough unselfish mentality," Karl said. "They have scorers, and they don't have playmakers. ...They will get better. But there is a foundation, a fundamental foundation they might be missing."
No one ever had such concerns about the Pierce-Garnett-Allen Celtics, or the James-Wade-Bosh Heat. Then again, no one ever called those teams fragile, either.
Will Irving choose to be a more willing passer? Will Love get more post-up chances, or adapt to a narrower role as a spot-up shooter? Will the bench evolve? Will anyone play any defense?
Will this group make the necessary sacrifices? Or will it collapse under the weight of expectations and egos?
The Celtics in 2007 made it all look so easy, three superstars with complementary skills uniting at the right time, with the right outlook, the right coach and the right supporting cast.
"It was sort of like the holy trinity or something, man," Pierce said, smiling again. "I don't know. It just, it came together."
Howard Beck covers the NBA for Bleacher Report. Follow him on Twitter, @HowardBeck.