It was the jewels which ultimately proved to be his undoing. Melkor, who covetted them, stole them after the poisoning of the two trees. Fëanor and most of the Noldor host swore the Terrible Oath of Fëanor and followed Melkor to Middle-earth. The events that followed make up much of the known history of the 1st age.
Of them, however Fëanor was never to know as he perished in the winning of Dagor-nuin-Giliath, reckless as he was in pursuing fleeing orcs into a great band of Balrogs. Though mortally wounded by Gothmog, his sons rescued him and bore him towards Mithrim. Looking upon the peaks of Thangoridrim he knew that the Noldor would never overthrow them and cursing Morgoth, died. His spirit was so fiery that it burnt his body to ash and drifted away like smoke. His like was never seen again.
Generated on Tue Nov 10 15:16:45 2020