The ending of Avengers: Endgame saw Steve Rogers/Captain America going back in time a nd returning all the past Infinity Stones to the moment they were taken and then spending his days dancing with the love of his life Peggy Carter, finally living the life he was denied.

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Avengers: Endgame Easter Eggs, Callbacks and Cameos 27 IMAGES

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When he returns to the rest of our heroes, he is an old man. That obviously raises the question of where he actually spent all those years. Was it in the MCU's main timeline 's past or an alternate one?It's such a great question that Avengers: Endgame directors Anthony and Joe Russo and screenwriters Christopher Markus and Stephen McFeely can't seem to agree on which one is actually true.Speaking to EW, the Russo brothers have taken the stance that Rogers' actions created an alternate, branching timeline as a result of him staying in the past. “If Cap were to go back into the past and live there, he would create a branched reality,” Joe explained. “The question then becomes, how is he back in this reality to give the shield away?”The Ancient One described that when you remove an Infinity Stone from the past, it creates a new, branching timeline from that exact moment. Taking this philosophy, when you travel to the past, it is technically your future, so anything you do in the past will impact your future self and not change any part from your past. Your history is set in stone, while anything after is an alternate timeline.However, screenwriters Markus and McFeely have taken the opposite stance . According to Markus when speaking to Fandango, the Ancient One was specifically stating that only when you remove an Infinity Stone from the past do you create an alternate, branching timeline.Considering Captain America simply went back in time to spend his days with Peggy following his mission to return the Infinity Stones, he would have not removed a stone and therefore would not have created an alternate timeline. Instead, it would have just meant that we had two Captain Americas throughout most of the MCU."That is our theory," Markus said. "We are not experts on time travel, but the Ancient One specifically states that when you take an Infinity Stone out of a timeline it creates a new timeline. So Steve going back and just being there would not create a new timeline. So I reject the "Steve is in an alternate reality" theory. I do believe that there is simply a period in world history from about '48 to now where there are two Steve Rogers. And anyway, for a large chunk of that one of them is frozen in ice. So it's not like they'd be running into each other."If he did go back in the main timeline, it does bring up a ton of other questions. If he was there throughout his past self being frozen, it would have been easier for him to hide. However, when all the events of the MCU began happening, why didn't he get involved and warn our heroes of the dangers to come? He could have potentially helped stop Thanos' Snap and so much more with his knowledge of the chaos to come.His interaction with Bucky also raises a few questions. The Russo brothers have confirmed that Bucky knew of Cap's plan, which was why he gave Cap such a big goodbye before he went on his journey to the past that was only supposed to take a few seconds."Especially when he says goodbye,” Joe explained. “He says, ‘I’ll miss you.’ Clearly he knows something.”Did they simply speak before? Did Old Cap visit Bucky in the past, meaning he already knew what was going to happen? Hopefully some of these questions and more will be answered in the upcoming Disney+ series focused on Falcon and the Winter Soldier. As for which stance is the truth, it is currently anybody's guess. IGN has reached out to Disney for an official word on which is correct, but until we hear, the question will remain - where did Captain America actually spend the majority of his life?For more on Avengers: Endgame, here's how time travel works in the MCU , plus we have breakdowns on how Captain America lifted Thor's hammer, Mjolnir the status of Gamora after Endgame ; and what Black Widow's death means for her standalone movie

Have a tip for us? Want to discuss a possible story? Please send an email to newstips@ign.com.Adam Bankhurst is a news writer for IGN who loves hurting his brain trying to figure all this time travel stuff out. You can follow him on Twitter @AdamBankhurst.