When Mystique dies

The "Original" Timeline (Mostly):

This was the initial run of films before Days of Future Past hit the reset button.

X-Men (2000): Introduces Wolverine, Rogue, Professor X, Magneto, Jean Grey, Cyclops, Storm. Focuses on the X-Men forming to combat Magneto's Brotherhood.

X2: X-Men United (2003): The X-Men unite with Magneto against William Stryker. Further develops characters and their powers.

X-Men: The Last Stand (2006): Focuses on the "cure" for mutants and the Dark Phoenix Saga. Many characters die or are depowered.

X-Men Origins: Wolverine (2009): A prequel focusing on Wolverine's past, his Weapon X origins, and his relationship with Sabretooth. This film immediately starts creating major continuity issues with X-Men and X2 (e.g., Deadpool's portrayal).

The Wolverine (2013): Set after The Last Stand, focusing on Wolverine's time in Japan. This film ends with a post-credits scene setting up Days of Future Past.

The "Soft Reboot" / Alternate Timeline (Created by Days of Future Past):

This is where it gets really complicated, as Days of Future Past attempts to merge and retcon the previous films.

X-Men: First Class (2011): A prequel set in the 1960s, showing the origins of Charles Xavier and Erik Lehnsherr, the formation of the first X-Men, and the Cuban Missile Crisis. This is chronologically the earliest film in terms of the main X-Men storyline, despite being released later. It established the "younger" cast.

X-Men: Days of Future Past (2014): This is the linchpin of the chronology.

Framing Story: Set in a dystopian future (2023) where mutants are hunted by Sentinels, directly following the original trilogy timeline.

Time Travel: Wolverine's consciousness is sent back to 1973 to prevent Mystique from committing an act that triggers the Sentinel program.

New Timeline: His actions in the past fundamentally alter the future, effectively erasing The Last Stand and The Wolverine from the "main" timeline and creating a new one. This is why Wolverine finds the original X-Men (Jean, Cyclops, Storm) alive and well at the end.

The "New" or "Altered" Timeline (Post-Days of Future Past):

These films largely ignore the events of The Last Stand and The Wolverine and build upon the changes made in Days of Future Past.

X-Men: Apocalypse (2016): Set in the 1980s, focusing on the emergence of the ancient mutant Apocalypse and the training of a new generation of X-Men (young Jean, Cyclops, Storm, Nightcrawler).

X-Men: Dark Phoenix (2019): Set in the early 1990s, this film attempts another adaptation of the Dark Phoenix Saga, but in the new timeline with the younger cast. It generally serves as the final main X-Men film before the Disney acquisition.

Deadpool (2016) & Deadpool 2 (2018): These films exist in a more meta, loosely connected way. They acknowledge events and characters from the Fox X-Men universe but often make jokes about the convoluted timelines. Deadpool 2 explicitly uses time travel. They are generally considered to inhabit the altered timeline.

Logan (2017): This film is a standalone masterpiece and is generally considered to take place in a bleak future (2029) of the original timeline, or at least a timeline that branches off before the happy ending of Days of Future Past. Its somber tone and definitive ending for Wolverine make it feel separate from the main continuity concerns.

Why it's a mess:

Retcons: Days of Future Past attempted a massive retcon, but it wasn't perfectly clean.

Prequels Creating Issues: X-Men Origins: Wolverine caused problems even before the major reboot.

Inconsistent Character Ages/Appearances: Characters like Emma Frost or Moira MacTaggert appear at different ages in different films, despite the timeline attempts.

Writer Changes: Different writers and directors had different visions, sometimes prioritizing their story over strict adherence to established continuity.

Standalone Nature: Films like Logan intentionally prioritize their specific story over fitting neatly into a larger, rigid chronology.

So, when you look at that meme of Iron Man looking confused, it perfectly captures the feeling of trying to make sense of the X-Men film chronology! It's less of a single "chrono-logical" path and more of a "branching, sometimes collapsing, occasionally time-traveling, and often contradictory" set of stories.