Kingdom Hearts is now regarded by many to be one of the most ambitious and successful crossovers of all time (sorry, Avengers: Infinity War). But that was not always the case, especially earlier in the 2000s when it began as nothing more than a mere concept.

Disney is notoriously known for being strict in terms of keeping their company’s family-friendly brand and maintaining a certain high level of quality, so what exactly convinced them to work with Square Enix? How did Kingdom Hearts creator Tetsuya Nomura get away with mixing Final Fantasy characters with decades-worth of beloved Disney properties?

Here’s the summarized story (via Anime News Network’s help):

-It all started when Buena Vista Games (or the now-defunct Disney Interactive Studios) decided to stop developing/publishing games themselves (most of which were low in quality) and move to focus on licensing Disney properties to other game developers/publishers. This was when Square Enix came into the picture and grabbed the opportunity for collaboration.

-In the very first meeting between Disney and Square Enix, newly-appointed director Tetsuya Nomura did the unthinkable. He rejected all of Disney’s ideas and proposed his own idea instead. Inspired by Super Mario 64, Nomura wanted an original character who journeys through the Disney worlds.

–Nomura’s idea was approved, albeit with one caveat; Square Enix couldn’t use Disney’s iconic mascot, Mickey Mouse. Disney eventually relented, but even then, Mickey Mouse was only allowed to appear once, and only from a distance. That’s why King Mickey only appeared once and for a very brief moment in the original 2002 Kingdom Hearts game (at the end of the game when he sealed the door to Kingdom Hearts).

–Ultimately, the Kingdom Hearts IP and any original character developed for use in the franchise belonged to Disney, including Sora, Kairi, Riku, and more. There’s also a reason why Tarzan never appeared in any of the Kingdom Hearts games after the first; Tarzan is co-owned Disney and Edgar Rice Burroughs Inc.

-As the Kingdom Hearts franchise became more successful, Disney’s licensing restrictions became more relaxed, allowing Square Enix to use more Disney properties and even to feature a lot more of Mickey Mouse himself.

-The next step on Nomura’s list was to create a Kingdom Hearts world based on a live-action Disney property. He later received permission for not only the 1982 Tron movie but also its 2010 sequel Tron: Legacy and Pirates the Caribbean franchise to boot.

-The reason why Kingdom Hearts managed to retain many of the original voice actors from Disney movies is thanks to Disney Character Voices International, a global company that manages the voice dubbing for all Disney properties. Examples include Jim Cummings reprising his role as Winnie the Pooh and Tigger, Kathryn Beaumont as Alice, and much more.

-Disney and Pixar didn’t have the best of relationships when the Kingdom Hearts franchise was just beginning in 2002, with bad blood between the two company’s head honchos Michael Eisner and the late Steve Jobs. It was later in 2005 when Bob Iger took over as Disney CEO that he acquired Pixar and put John Lasseter in charge of the animation studio.

-It was only when that happened that Pixar properties could finally be added into the Kingdom Hearts franchise. The upcoming Kingdom Hearts 3 is set to be the first game in the franchise to feature a Pixar property, namely: Toy Story’s Toy Box.

-Nomura’s level of creative freedom with Disney/Pixar properties now with Kingdom Hearts 3 is such that the story involving Big Hero 6’s world in the upcoming game will actually take place after the events of the 2014 movie, with Sora, Donald, and Goofy meeting Hiro and his already-established team.

It’s amazing how far the Kingdom Hearts franchise has come since 2002. Kingdom Hearts 3 is slated to release for the PS4 and Xbox One on 29 January 2019. In the meantime, check out our ranking of all the Kingdom Hearts games from best to worst here.