The Proto-Elves - also known as Ancient Elves or Ancestor Elves - were a race of people originally foreign to the continent of Artograch, being ancestors to today's High Elves, Wood Elves, Humans, Orcs, and Dark Elves. In nutshell, the original Elves.
The Proto-Elves first arrived to the Western coasts of Continental Artograch between 2500 and 2000 BEKE, colonizing much of what is today Dragoc first, then Froturn, Western and Central Etrand, and Hulra as well as Neressa.
After the initial wave of colonization, Proto-Elves started to evolve and diverge from each other depending on the areas they settled at. Around 1100 BEKE, this divergent evolution was finalized and from that point we can talk about three separate Elven races having emerged from the Proto-Elven ancestors: those Proto-Elves who settled in future Dragoc evolved into the Wood Elves, those Proto-Elves who settled in future Froturn and Neressa evolved into the High Elves, those who settled in future Etrand and Hulra became the Humans.
The origins of the Proto-Elves are shrouded in mystery, and the only semi-reliable source is from religious teachings. Both High Elven Titanist and Wood Elven Naturalist mythology places high emphasis on the Proto-Elves, and both religion's religious literature devotes quite a few episodes to the Proto-Elves.
Both religions teach that the Proto-Elves lived on their own insular paradise, an Island of Eden of sorts, where they happily coexisted with the nature, never eating meat, having no violence at all, harvesting only as much fruits, vegetables and cereals as necessary not to starve. That would all change one day, when one Proto-Elf ate meat, loved it's taste, and began spreading his new way around. Eventually, the Proto-Elves formerly living in fraternity and brotherhood started feuding with each other. The ocean began slowly but surely swallowing up the island, forcing it's inhabitants to flee - hence the Proto-Elven landing on the West Coast of Artograch and the colonization of Artograch.
While it is an indisputable fact of history that the Proto-Elves came by boats to Artograch, and made their first appearance on the West Coast, claims that they were previously a pacifistic people are hard to believe, considering that the Elven colonists had access to iron weapons, while the native populations of Artograch at the time - Lizardmen, Halflings, Dwarves, Gnomes, Goblins and Ogres - only had access to bronze weapons, and how violently they expelled or exterminated native populations to make space for Elven settlements. It is also worth mentioning that while most native races to Artograch were primarily invested in farming or fishing, the Proto-Elves were originally primarily hunters and animal-herders, adopting farming and fishing only later (which is rather ironic, considering that they allegedly originated from an insular realm and arrived by ships).
Recently, several less religious historians have also began questioning whether the island the Proto-Elves allegedly originated from even existed in the first place to begin with. While several now-uninhabited islands were found south-west of Dragoc, they are largely tropical or sandy-desert islands, not matching the mythological description of the Proto-Elves' homeland at all. The fact that no tools or other kind of artificats of possibly Elven origin were found at those islands at all doesn't help answering this question.