This is something that has been bothering me for the longest time. Many of the Pokémon games are quiet when it comes to timelines, and this thread is here to attempt to place the Pokémon games in a reasonable timeline. If you guys have any thoughts about what you think it would be like, post in this thread!
Oof, that's a tough one... Personally, I believe in the whole multiverse thing as told by Zinnia in OR/AS. Spoilers for the Delta Episode btw: Spoiler "My people know it. From generation to generation, we pass along lore about the distortions in the world borne from the Mega Evolution mechanism. And about the existence of another world, which we have long observed to be just like this one and yet not the same... That's right. A Hoenn region that's almost exactly like this one we live in. Filled with Pokémon and people like us. A world where maybe the evolution of Pokémon took a slightly different path, where Mega Evolution is unknown... A world where that war 3000 years ago... never happened. A world where the ultimate weapon was never even built." -Zinnia She's essentially telling us that the newer generation of games starting from X and Y are split into another timeline all together, one where Mega Evolution is a thing. Which makes creating a timeline for this series all the more confusing... Maybe not as a giant mess like the Zelda timeline is, but you get the idea.
There is an official timeline for the the first five generations actually. Red, Green, Blue, Yellow, Leafgreen, and Firered are at the same time as Ruby, Sapphire, and Emerald. Based on the Mew event that is in both Fr, Lg, and RSE. GSC, SSHG was two years after those games and tied in with DPPt. Then BW. Which have no other part that happens at the same time. B2W2 are after BW, obviously. But after this it gets hard to determine the truth. I do believe that all the games that have Mega Evolution belong to another universe iwhich Zinnia said. It is said that B2W2 are tied with the XY games, but that makes no real sense due to the presence of Mega Evolution.
I also believe the Multiverse Timeline theory. I'm pretty sure the Mega Evolution Timeline is ORAS--->XY--->SM
If we go by anime, then I say almost separate timelines or just a weird continuation. For the games I think they all pretty much go on at the same time, other than the gold/silver/crystal games since that is the return of team rocket. I can see it also being one after another since tech slowly increases with each game, the fact it hasn't spread back kinda shows it being a progression of time. Also, now that we see Red and Blue have aged, it kinda shows time moving.
I'm a fan of the Multiverse Theory. Spoiler Of course it's canon that G/S/C comes after R/B, B2/W2 comes after B/W, S/M comes about 20 years after R/B, but everything in between is...vague, to say the least. I have a weird headcanon that R/S/E occurred around the time of D/P/P, or at least ORAS did. The meteorite was pulled into Hoenn by the huge spacial/temporal energy influx coming off Sinnoh while Cyrus was going about his crazy plan. In turn, the energy from raising Groudon/Kyogre affected Rayquaza, which is why the dragon was able to help you in Delta Episode. PKMN B/W has ties to the past too, and I wonder if the dragons of truth and ideals were around while Groudon and Kyogre were dueling it out. I don't know anything more, but I think third through fourth gens occurred after R/B/Y, while fifth happened during the first generation. Maybe Team Plasma has something to do with Mewtwo.
