RELATED: The 8 Different Witcher Schools, Explained They colonized a large part of the Continent - though through peaceful means - and lived in relative peace until the Conjunction of the Spheres.
The elves arrived roughly 2,500 years before the humans, most likely through a portal from another world. The humans are the youngest species on the Continent, but the elves are the second-youngest, having arrived later than the other members of the Elder Races (that also include dwarves and gnomes).
But a big part of the story, be it the books or the games (and possibly even the Netflix adaptation in the future), is the war between humans and elves. If there's anything in abundance in the world where The Witchertakes place, it's prejudice - be it towards non-humans, witchers, sentient monsters, rich people, poor people.