Once upon a time, was just an idea in Joe and Anthony Russo's collective think tank. The 2016 film sees the Avengers divided into factions, with Captain America/Steve Rogers (Chris Evans) opposing legislation to regulate the heroes' actions and Iron Man/Tony Stark (Robert Downey Jr.) supporting it. Matters are more complicated when Steve is forced to defend his lifelong best friend Bucky Barnes/the Winter Soldier (Sebastian Stan), who was brainwashed into murdering many innocent people, including Tony's parents.

Interestingly, the brothers recently revealed the humorous story behind how they managed to get approval for as bold an idea as pitting the two biggest faces of the MCU against one another. In a new profile from The Hollywood Reporter, the Russos explained that they had two major hurdles in getting the pitch off of the ground.

Naturally, they had to convince MCU architect Kevin Feige. However, Anthony explained how the Marvel Studios boss responded: "We pitched Kevin on the idea and Kevin goes, 'All right, I buy it. Now you guys got to go get Downey.' And I was like, 'What do you mean we got to go get Downey? Aren’t you coming?' And he didn’t."

Joe then told the story of how they visited Downey to woo him as a star for their next film. The Iron Man star "was sitting on a chaise lounge, splayed out like a king, on the roof of his office in Venice," when the brothers "showed up [after they'd] been rehearsing this pitch." He then pointed out the pressure of the situation: "You’re literally pitching the biggest movie star in the world to take his giant cash cow character and convert it into a villain."

Anthony also noted that they were taking this big swing for a Captain America film, not even one where Iron Man would be the title character. Joe called Captain America: Civil War "the pitch of [their] lives," adding that the actor "liked the risk, to Robert’s credit, and that choice led the explosive upside to Infinity War and Endgame."

Captain America: Civil War was a risky endeavor. After all, However, clashing as coworkers is very different from fighting over potentially dangerous legislation or protecting the murderer of one's parent. The repercussions of pitting the two franchise leads against one another would fundamentally, irreparably alter its trajectory.

It's understandable that the Russos would be nervous to pitch a story that paints Iron Man as an antagonist for Captain America. If poorly executed, it could tarnish the reputations of both characters or turn fans off from the franchise. Alternatively, that kind of risk may have been what made Downey accept the script.

While the film was a massive gamble on Marvel's part, Captain America: Civil War went on to become one of the most successful and beloved entries in the MCU. Ironically, the most compelling part of the film was the debate between Captain America and Iron Man, as both had valid points with regard to the Avengers and to Bucky's past crimes.

Additionally, the movie also brought Black Panther and Spider-Man into the MCU, which only made the excitement surrounding the film more strong. was an incredibly ambitious film, between the new characters and the believable conflict between the MCU heroes. Clearly, Feige and Downey were right to trust the Russos.