Sinnoh is a region featured in the fourth generation of Pokémon games_Pokedex). The fourth generation of the Pokémon franchise began in 2006 with the release of Pokémon Diamond and Pokémon Pearl, and it introduced many new features to the series, including new Pokémon, evolutions for Pokémon from previous generations, and the introduction of the Sinnoh region. The Sinnoh region is the territory where most of the fourth generation games took place, and it is said to be the oldest region in the world and where all Pokémon originated from. The Sinnoh region is also home to some of the most important legendary Pokémon in the franchise, including Palkia, Dialga, and Giratina, who form the creation trio, and Arceus, the supposed "first Pokémon".