When Denethor, leader of the Green-elves, was killed by Orcs on Amon Ereb in the First Battle of Beleriand, some of the Laiquendi fled westward to Doriath and settled in Arthórien. These became known as the Guest-elves.
The Guest-elves had their own chief (of whom Saeros was the son), and they had a permanent place in the council of Thingol. However, some of the Guest-elves were "darkhearted", and they did not "mingle happily with the Teleri of Doriath". Neither were they friends to the Edain of Estolad—the mannish region situated just east of Arthórien, into which the Guest-elves often wandered by crossing the River Celon.