Elves of Beleriand
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For three ages after the departure of the Vanyar, Noldor and Teleri to Aman, the Elves who inhabited Beleriand comprised that part of the Telerin people who remained in Middle-earth, known as the Sindar or "Grey-elves" after their king, Thingol Greycloak of Doriath.
At the rising of the Moon in the beginning of the First Age, many of the Noldor returned to Beleriand from Aman to make war on Morgoth. While there was some enmity between the Sindar and the Noldor (especially the Sons of Fëanor), the two peoples lived together in the face of their common foe, Morgoth Bauglir.
Finally, a small part of the Nandor, kin of the Sindar who had turned aside from the westward journey east of the Misty Mountains, entered the land of Ossiriand during the First Age. Though these people, called the Laiquendi ("Green-elves"), played little part in the wars against Morgoth, they are accounted a part of the Elves of Beleriand.