The latest mainline entry in the Pokemon series is also the earliest game in its timeline. Arceus takes place 2,000 years before the events of Pokemon Red and Blue
Red and Blue were the first American entries in the Pokemon series, released by Game Freak in 1998. The protagonist, Red, sets out from Palette Town in the Kanto region on an adventure to earn eight gym badges and become the Pokemon League Champion.
Game Freak launched Ruby and Sapphire in 2002, but the games take place at the same time as Red and Blue. The protagonist of the third generation fights either Team Magma or Team Aqua, villainous organizations bent on terraforming the planet.
Pokemon Gold and Silver hit stores in 2000, and serve as direct sequels to Red and Blue. Players journey through the Johto region, which lies immediately west of Kanto. After gathering eight gym badges in Johto, the protagonist can travel east across Mt. Silver to revisit the Kanto region.
According to the developer, 2007’s Pokemon Diamond and Pearl take place at the same time as Gold and Silver. The Sinnoh adventure is disconnected from the events of the first three Pokemon titles, though. There’s no evidence in the game to indicate that it takes place before or after any other entry.
Pokemon Black and White came out in 2010 and featured a new regional Pokedex of 151 new Pokemon. Players visit the Unova region, which is geographically distant from Kanto, Sinnoh, and Hoenn. Black and White take place approximately ten years after Gen 2 and Gen 4