It feels like ancient history at this point, but after Game 2 of the 2015 NBA Finals last June, LeBron James told reporters that he had “other motivation” for wanting to win a title with the Cavaliers (aside from obviously wanting to win the first title for a Cleveland sports team in more than 50 years).

“My motivation is to make sure my guys are ready and prepared every night we step on the floor,” he said. “And I have some other motivation that I won’t talk about right now.”

LeBron refused to reveal what that motivation was—forcing us to guess what it might be—but it was clear that something was driving him. He promised to tell reporters about it if the Cavaliers won the championship. “I hope we win,” he said, “so I can tell y’all.”

The Cavs didn’t win the title in 2015, but they did win it in 2016 by becoming the first team in NBA history to rebound from a 3-1 NBA Finals deficit in their rematch against the Warriors. And while most people had long forgotten about LeBron’s “other motivation” by the time Sunday night rolled around, ESPN.com reporter Dave McMenamin didn’t. He got a chance to ask LeBron about it after Game 7 of the Finals, and according to him, LeBron finally revealed his secret motivation for wanting to win a title with the Cavaliers.

So, what is it? Well, here’s a segment McMenamin did on SportsCenter early Monday morning, where he talked about how someone in Miami told LeBron he was making the “biggest mistake of his career” by leaving the Heat in the summer of 2014. LeBron told McMenamin that that is what has fueled him for the last two seasons:

“He wouldn’t name names,” McMenamin said, “but [there was] someone in Miami who told him—someone he trusted, someone he believed in—who said, ‘You know what? You’re making the biggest mistake of your career.’ He said it really hurt him to hear those words, and clearly, tonight, winning the third championship, bringing a championship to Cleveland, his hometown, he made, I think, maybe the best choice of his career.”

McMenamin also spoke in more detail with The Undefeated about LeBron’s secret motivation:

LeBron left his motivation shrouded in some mystery; he wouldn't say who in Miami told him it'd be a mistake for him to come back to Cleveland (this might be a good place to start). But we finally know what's been driving him to try to win the third title of his career.