Broad strokes timeline of the Suocéverse's Mainline World, that is the “trainerverse” that maps to the default world where the mainline games and anime take place.

Range: <10⁸ years into the past.

The world came into being at a time of around a few thousand million (~10⁹) years before the The Present Era. In this sense, Pokéarth has an early geological history not too different than that of IRL Earth.

“Pokéarth” thus defined, it was one of a number of worlds (planets) that the Creation and Lake trios seeded and used as playground to learn how to create intelligent life.

Range: a few tens of millions ~ a few hundred thousand years into the past.

This era wraps a number of geological eras during which the Creation and Lake trios left Pokémon life in this world to (Darwinially) evolve on their own. However, every once in a while some or all of the members of the Sextet would come to “Pokéarth” and spawn great cataclysms to rid of all Pokémon population in order to start anew. Every time, only a few species managed to survive to the next iteration, among them the species that came known to be in Present Era as “Legendary Pokémon”.

At some point very late in this era, Humans were introduced into this world.

See Mainline Ancient History.

Range: ~300 000 years → ~46 000 years into the past.

Range: ~46 000 → ~4 000 years into the past.

See Previous Era.

Range: ~4 thousand years into the past → contemporary decades of the present.

The present era covers the time periods which the animeverse documents as “history” rather than “prehistory”. Starting around three thousand years before the events of the mainline games, it spawned the birth and lives of a number of cultures and nations that shared Pokémon Training as a common background element.

See The Present Era.

Undetermined.