The Fox X-Men cinematic universe is complete and one of the biggest issues with the franchise appears to be the timeline. Most people just agree that the X-Men movies do their own thing and don’t worry about continuity. However others cannot get over the “messy” and “complicated” timeline, the movies take place in. However, I personally think there is a very specific timeline that is followed. You just have to allow the comic nerd inside of you to accept time travel, alternate realities, off-screen resurrections and the occasional continuity error that all movies have. Follow along as I show you the unofficial, but accurate, X-Men timeline.
The Original Timeline
X-Men: First Class 
This is the beginning of the timeline. Professor Xavier can walk, Magneto isn’t a villain, and mutants do not have a safe place to call home. The X-Men have only begun to form as some of the mutants, that rule the franchise, get an origin stories. This movie ends with an explanation for why there is such a complex dynamic between Erik and Charles.
X-Men Origins: Wolverine 
Logan comes into the story. We see his immortal origin and relationship with the Weapon X program. He is turned into a monster, not just by the experimentations but also by the betrayal of everyone he was close too. The events of this movie send him into an unexplored world with no memory of his past or how he got his metal claws.
Years after the collapse of the Fist Class, Xavier has a new team of X-Men. Equally Magneto has formed a group called The Brotherhood of Mutants. These two old friends have to fight in order to protect their race. Wolverine, still without memory, finds the X-Men and joins the team.
X2: X-Men United 
The government program, Weapon X, never stopped experimenting on mutants. They find Logan and destroy the safety of Xavier’s school. Logan has to try to remember his past in order to save his friends and students. The battle pushes the team to a limit they haven’t reached before, causing Jean to gain the attention of a power she can’t control.
X-Men: The Last Stand 
Jean Grey is taken over by the Phoenix Force. She goes on a wild rampage, killing Scott and Charles. Meanwhile there is a potential cure for the Mutant gene. Magneto takes this opportunity to manipulate the Phoenix and attack the facility making the cure; ultimately failing. Wolverine kills Jean in order to stop her.
The Wolverine 
Haunted by the events of TLS, Logan goes off the grid to live in the woods. He gets sucked into a Japanese family’s story because of a person he saved in his past. He eventually comes to accept his fate as an immortal. Wolverine also learns a lesson in the downside of becoming a hero and how you cannot save everyone.
X-Men: Days of Future Past (Future) 
The apocalyptic future for all mutants eventually shows up. The final reserve of mutants are pinned together in a fight against extinction. There are no more heroes or villains. The Mutant cure has worn off and the mutants effected have gotten back their powers. Charles is alive again. This is the fate of the original timeline, and without the successful time travel, this was always going to happen.
The original timeline ends in destruction for the mutant race. Without the success of the time travel, the mutants are hunted down and killed. Logan is able to escape with Charles and live in hiding. Eventually the threat of mutants goes away and so for the sentries. Logan is the finale to the dark timeline; a nightmare for mutant kind. This is the future that all of the X-Men and Brotherhood have fought to prevent. The alternate reality created when Logan goes back in time saves them all from this ending, even if it causes other catastrophes.
The Alternate Timeline, Created by Days of Future Past
X-Men: First Class 
The events of First class are unchanged. This is the canon version of the original story for Charles, Erik, Raven, and Henry. Magneto eventually is arrested for his crimes against the nation and sent to prison.
X-Men: Days of Future Past (Past) 
Because of time travel, the events of Days of Future Past changes the way the universe would go. Without Wolverine going back in time, Charles wouldn’t have broken Erik out of prison with Quicksilver. The scene at the baseball field never would have happened. Mystique wouldn’t have abandoned Magneto. Even though the end result is a happier life, the events of this movie alter the entire timeline creating a new reality.
Alternate Version of Wolverine Origins [1970s-1980s]
The Weapon X program got ahold of Logan at the end of DOFP differently than the original timeline. So he was a prisoner instead of a manipulated volunteer. We wont know how this version of his time in the program goes, or what he does after he escapes. But we do know eventually he finds his way back to the X-Men.
X-Men: Apocalypse 
The biggest difference in this timeline was Apocalypse’s resurrection. This caused several mutants to become ‘The Horsemen’ as well as bringing other mutants together, including Nightcrawler years before he was going to meet the X-Men. They have to engage in a battle that was more powerful than they encountered in their original timeline. Specially effecting the Phoenix Force and Jean’s destiny.
X-Men: Dark Phoenix 
The Phoenix Force interacts with Jean Grey sooner than it would have in the original timeline. Accompanied with an alien race that wouldn’t have witnessed Jean taking on the power in space. Jean accidentally kills Raven. Jean gains some control over the Phoenix and ends up leaving the planet. Xavier steps down as headmaster of the school.
Alternate Version of the Original X-Men Trilogy [2000’s-2020’s]
We will never see this version of the events form the original trilogy in the new timeline. Mystique never helped Magneto because she is dead (as far as we know). Jean comes back to Earth and the Phoenix is either gone or under control. Quicksilver is a team member. Wolverine ends up finding joining the X-Men still. Adventures happened, but not the same way we will remember them.
X-Men: Days of Future Past (Ending) 
Although the alternate timeline created a lot of chaos, in the end Wolverine comes back to a reality that is much safer than the dystopia in Logan. The school is intact and majority of the main characters are alive. No one in this reality has experienced anything from the original timeline, other than Logan. The wild ride that is the X-Men universe got a happy ending.
Timeline observed and catalogued by: Troy Smith
Oh… And Deadpool [Who really cares]
Deadpool is a character that sit outside of time and space. He is aware that there are alternate timelines. Furthermore he is aware that these are movies. In the sequel, Cable brings the element of time travel in that causes so much chaos that it would never work. Deadpool doesn’t need to fit in the timeline, he just needs to be himself. And that is good enough.