The eclipse was remarkable. The trade was otherworldly.

The Boston Celtics have traded Isaiah Thomas, Jae Crowder, Ante Zizic, and the Brooklyn Nets’ 2018 unprotected first-round pick to the Cleveland Cavaliers for Kyrie Irving, as first reported by The Vertical’s Shams Charania.

The Celtics complete their third significant trade of the offseason, after sending the first pick in this year’s draft to Philadelphia for the third pick in the draft and the Los Angeles Lakers’ protected 2018 pick. They then shipped longtime starting guard Avery Bradley to the Detroit Pistons for Marcus Morris.

In an offseason filled with blockbuster trades, the Celtics have made the most significant investment yet to acquire one of the best young players in the NBA in one of the most monumental player swaps in recent NBA history. The Celtics are exchanging one superstar for another, paying a shockingly steep price to mitigate the risk of paying Thomas for the back-end of his prime while acquiring a superstar who may have another tier to climb.

The trade comes a month after Irving’s trade request to Cavs owner Dan Gilbert was leaked, resulting in one of the most surprising exits of this era. Irving asked out of the perennial favorite in the Eastern Conference as LeBron James’ sidekick to find a more stable franchise where he could be the featured star. Irving will find that stability in Boston, where Danny Ainge has run the front office for over a decade and Brad Stevens has established one of the most widely respected coaching programs in the league.

In Irving, the Celtics extend the cost certainty of their star guard for another year while maintaining comparable elite production. They no longer have to decide if a recovering Isaiah Thomas is worth maxing out, as Irving is a no-brainer and has another contract before he reaches the age Thomas will hit in free agency.

Ainge said Tuesday that, “contracts do play a part in the trade, no question about it,” and would eventually decline to comment on the possibility of maxing out Kyrie in two years. But the Celtics have had their eyes on the luxury tax bill since the cap projections started to collapse this spring and were wary of the potential $200 million bill that could rapidly approach if they signed Isaiah to a max deal, sources told CelticsBlog.

The outcome is another elite player with little injury concern and several years before he hits his prime, regardless the personnel cost. Making this deal at this price reflects an elevated risk with Isaiah Thomas’ longevity, a player recovering from a hip tear entering his age-29 season with a game that thrives on extreme torque, agility and athleticism. Now, Ainge readjusts the team’s timeline to fit closer to their young elite talent, something he emphasized Tuesday.

“I think it’s extremely rare to be able to trade for a 25-year-old player that’s done what he’s done in his career and the offensive weapon that he is.” Celtics President of Basketball Operations Danny Ainge said on a conference call after the trade was announced Tuesday night. “We know we’re paying a heavy price. We loved the guys that were here and we didn't really wanna give up any of those pieces to make this deal work, but we're excited to have Kyrie.”

Irving has three-years remaining on his contract, with a player option after the second year that he will likely exercise. He waived his trade kicker to facilitate the deal per Charania, saving the Celtics over $5 million. Ainge is confident that Irving is not much of a flight risk, despite the circumstances surrounding his arrival to Boston.

“We feel like we have done a lot of homework. We feel comfortable with who Kyrie is, and who he can be. We feel like his best basketball is still ahead of him. But you can be assured that we did talk many people and did a lot of homework.”

But the Celtics have paid a surprisingly steep price to acquire Irving, including the prized Nets pick projected to go high in an incredibly hyped draft next year and promising rookie big Ante Zizic. They do this to acquire a player comparable to the one who led them last year, with little indication that this will push them to a new level this season. They even solve several problems for Cleveland’s rotation, making them potentially more potent than last year if Isaiah Thomas makes a full recovery like Ainge projected Tuesday.

This trade is, at its core ideology, a bet that Kyrie Irving’s prime will transcend the player he is today. That he has a James Harden level of offensive dominance ready to be unleashed. Irving showed Ainge close up how elite he can be in the conference finals. Ainge thinks he can be that guy on a nightly basis now that he doesn’t have to defer the ball and choreography to LeBron James.

But a major task will be adjusting the system to maximize what Kyrie has to offer. Stevens’ offense thrived off of Thomas’ prototypical skill set last year, a guy who takes his shots behind the arc or in the paint and works off split actions, DHOs and other motion actions seamlessly. Irving comes from a more isolation and transition focused system, which may have been a shackle to him even if it appeared to be built to fit his skill set.

They also part ways with Jae Crowder, a crucial core piece to the Celtics for years who was necessary for salary matching. But with Morris in the fold and Jaylen Brown slated to take a big leap in year two, Crowder’s absence is palpable. While he is renowned for providing such value on his below mid-level contract, Morris provides comparable value at an even lower price tag for just one year less.

“We know we’re paying a heavy price. We loved the guys that were here and we didn't really wanna give up any of those pieces to make this deal work, but we're excited to have Kyrie.” — Danny Ainge

The Celtics will likely start Irving, Gordon Hayward, Jaylen Brown, Al Horford, and one of Aron Baynes or Marcus Morris. There are now just four Celtics remaining from last season in Horford, Brown, Marcus Smart, and Terry Rozier. Smart, who is still on his rookie contract, is now the longest tenured Celtic on the roster.

But the sticking point of this trade was the inclusion of the Nets pick without any protection. As negotiations escalated Tuesday night in a race to the finish, the pick was the lynchpin. Two months ago, the Celtics traded the first pick and received the rights to the Los Angeles Lakers’ pick next year if it falls 2-5, with the pick converting into the Sacramento Kings’ 2019 first-rounder if it falls outside that protection zone. This unique crafting of protections was a shrewd compromise by both sides to give the Celtics a higher chance at a top pick over multiple years while allowing Philadelphia to hold on to the pick if it lands at the top.

Yet in a trade where the Celtics apparently held significant leverage, they kissed the Nets pick goodbye with no restrictions. While the grip on the Nets pick got a little looser when Nets GM Sean Marks made a series of trades to bolster his roster, it still retains tremendous value well beyond an add-on in an already stacked offer for a player who turned in an official trade request. Surrendering a major pick without receiving one in return wasn’t unchartered territory for Ainge, who finally revealed in the post-mortem that he had been willing to make this sacrifice in the past.

“We offered first round picks of this caliber for a handful of players, a few players at least in the past. The trades just didn’t go through. But Kyrie is unique and I think this is an opportunity, a trade that we wanted to do that we felt was best for us at this time.”

But what remains unanswered is how the Celtics paid a king’s ransom for a prince who declared he wanted a new kingdom. Irving’s trade market was dying in the western conference – a preferred destination for a Cavs team hoping to remain atop the weakened East – when teams like Phoenix refused to include top prospects like Josh Jackson. Boston managed to pull the deal off without including an equivalent prospect in Jayson Tatum or Jaylen Brown, but lost a good prospect in Ante Zizic and a pick that, even if the Nets do improve with a revamped roster and a healthy Jeremy Lin to climb out of the top of the lottery, it still feels like a bullish price in a bear market.

From Ainge’s perspective, he’s been trading in a rigged game for awhile now, where the deck is stacked against him because of all the cards he was carrying in his back pocket. In his draft night press conference, when CelticsBlog asked him if he felt he was being held to a higher price because of the assets in his portfolio, Ainge said:

“I think there’s some truth in that,” Ainge said draft night. “I know when I'm trying to do deals with teams, and I'm looking, ‘Oh, I'm going to call that team because they have something I'm really excited about.’ I think people around the league know what we have and they are asking for some of our prime real estate.”

Now some of his most luxurious properties are heading to the shores of Lake Erie. The two players he swindled from their previous employers on which he built this Stevens era are gone. An anticipated young center who was looked at as one of the best rookie prospects is exiting. The final and most illustrious of his crown jewel Nets picks is someone else’s mantelpiece now.

“We still value that pick,” Ainge said. “We valued it from the time we got it. It’s still very valuable. I don’t think that’s gonna change. But obviously we valued Kyrie more. It’s that simple.”

While Ainge has preached the underlying value of draft picks in their versatility and low cost, his message Tuesday night fell in line with the one major criticism that flew in the face of that philosophy for years: Unpredictability.

Top draft picks are extremely desirable, but the success rate of getting a franchise player is maybe 50-percent after the first pick. There were plenty of trade targets on the market that got close to being the ultimate sure thing. Jimmy Butler and Paul George had age or contractual concerns that made things just short of optimal. DeMarcus Cousins had a list of caveats that stretched from Sacramento to New Orleans. But Irving is younger, cost-controlled and potentially better than all of them.

“We have a player that proved to be a sure thing,” said Ainge. “We know how unpredictable the draft can be. We have a 25-year-old All-Star, Olympian, world champion, top notch scorer at age 25, and that is very rare. And you do pay a heavy price for a player of that age and that caliber.”

This type of roster turnover is emotionally grueling on all involved. Ainge spoke with his now former players by phone when the trade was agreed, which he hinted was a painful experience.

“I’m not gonna share our private conversations with Isaiah as you could imagine,” Ainge said. “I’ll leave it to your own imaginations to realize how difficult that conversation might have been, for me and for Isaiah.”

Of all the moves Ainge has made in the Stevens era, trading Thomas was probably the biggest challenge. Beyond his cult-hero status in Boston, he was an energetic recruit for Al Horford and Gordon Hayward and reached unforeseeable levels of dedication when he dominated in the playoffs through the pain of losing his sister Chyna and dealing with a hip labrum tear.

“Trading both guys was tough,” Ainge said. “But you know, Isaiah had an amazing season this year and entertained us all, the whole city of Boston, and everybody fell in love with him. He’s such an underdog because of his size and his heart and his spirit in which he plays, and you know it was very challenging to make this decision.”

So much of the Celtics identity was built on the backs of those two stalwarts, players who almost immediately transformed the energy and style with which the Celtics played upon their arrival. Thomas’ ascension to NBA stardom was as rapid as it was remarkable. Crowder became one the league’s best role players, a true two-way player who made up for some skill shortcomings with tenacity and athleticism. They left a permanent impression on a team that they leave behind with only four former teammates remaining. For now.

A troubling consequence of this trade is the subtextual cruelty that emerges when business outweighs loyalty. Ainge made it clear that he would be willing to move on from franchise cornerstones after their prime to maintain forward momentum when he traded Paul Pierce and Kevin Garnett — or tried to trade and then low ball Ray Allen. But Ainge sacrificed Thomas and Crowder in their primes, two players who have earned unconditional loyalty more than any Celtics since Pierce was traded away. The ramifications could have come in prospective free agency, but they are capped out to the point that they won’t be signing any long-term free agents for the foreseeable future.

When Ainge was asked how he felt overall about his offseason, he graded it an incomplete. Perhaps there is just the remaining business of adding more players on the veteran minimum. Maybe there is more.

“Why don’t we talk about that when the summer's over,” Ainge said with a big laugh. “Let’s wait and see what else happens.”