In Tolkien mythology, the Elves were the first children of Eru, the One, whom they called Ilúvatar. The Elves were not subject to disease or physical aging, though they could be killed by violence or by wasting away and losing the will to live. They were otherwise essentially immortal.
Some, known afterward as the Eldar (People of the Stars), were brought by the Valar from Middle-earth to Valinor, where they were taught by the Ainur. But after the Silmarils were stolen by Melkor, some of the Elves returned to Middle-earth, where they remained until the end of the Third Age.
The Firstborn, the Elder Children of Ilúvatar, conceived by Eru alone in the third theme of Ainulindalë, the eldest and noblest of the speaking races of Middle-earth. They awoke by Cuiviénen, the Water of Awakening in the far east of Middle-earth, in the starlight of the Sleep of Yavanna, as the Sun and Moon had yet to be created. The first elves to awake were three pairs: Imin ("First") and his wife Iminyë, Tata ("Second") and Tatië, and Enel ("Third") and Enelyë.
Imin, Tata, and Enel and their wives joined up and walked through the forests. They came across six, nine, and twelve pairs of elves, and each "patriarch" claimed the pairs as his folk in order. The now sixty elves dwell by the rivers, and they invented poetry and music in Middle-earth (the continent). Journeying further, they came across a band of Elves watching the stars, which Tata claims as his. These were tall and dark-haired, the fathers of most of the Ñoldor. The ninety-six elves now invented many new words. Continuing their journey, they find twenty-four pairs of elves, singing without language, and Enel added them to his people. These were the ancestors of most of the Lindar or "singers", later called Teleri. They found no more Elves; Imin's people, the smallest group, were the ancestors of the Vanyar. All in all they numbered 144. Because all elves had been found in groups of twelve, twelve becomes their base number and 144 their highest number (for a long time). None of the later Elvish languages had a common name for a greater number.
At first the elves sang with grace and merriment without speech but soon they developed speech and spoke with words, so their first name for themselves was Quendi (The Ones Who Speak With Voices). Since the first thing they saw when they awoke were the stars they also called themselves the Eldar (People of the Stars). Later, the name Eldar was used only for those who were part of the Great Journey to Aman.
Discovery and Sundering
The elves were content and dwelt long under the stars of the forest Cuiviénen. However, Melkor, the Dark Lord was aware of them and their location before the Valar, and during this time he sent evil spirits to spy on them and do harm to them and some of these early elves ran away from home in blind fear and were taken by Melkor or one of his agents. These elves were never seen again and were taken to Utumno and twisted and mutilated until they became the Orcs. So when they were discovered by the Vala Oromë during his travels throughout Middle-earth, some elves were afraid and hid but the faithful ones that stayed soon found out that he was nothing to fear and met with him. Oromë loved them and gave them the name Eldar (People of the Stars).
Oromë spent some time with them and then returned to Valinor to tell Manwë of the finding of the Firstborn of Eru Ilúvatar. He then returned to live with elves for a time learning about them. It was after this that the Valar decided to protect the elves by ridding Middle-earth of Melkor and his evils. The Valar made war upon Melkor and set a guard on Cuiviénen. The elves knew nothing of the war save that the earth shook and thunderous lightening was seen in the north. After the removal of Melkor, Oromë returned with a summons of the Valar to Aman. Some elves were afraid as they felt the tumults of the Valar’s war on Melkor and relented. Knowing this, the elves chose ambassadors one from each kindred and they were Ingwë, Finwë, and Elwë and they went to Valinor as representatives of their people.
When the three returned, they spoke to their people of the beauty and bliss of what they had seen and urged them to travel to Valinor and abide there, thus began the Great Journey, also known as the Sundering of the Elves. All of the elves agreed save for the Avari who chose to remain in Middle-earth. Led by Oromë, the elven kindreds marched out of Cuiviénen but as they moved out of the forest area and saw the black clouds surrounding the north where Melkor had once lived, some grew afraid and turned back to Cuiviénen. The rest continued albeit slowly often stopping until Oromë returned but were curious by what they saw.
The Vanyar and the Ñoldor, who were most eager to reach Valinor pressed on with the greatest speed and were the first to reach the coasts and to be taken to Valinor on an island that the Vala Ulmo guided across the Belegaer (Great Sea). The Teleri were the slowest of the group as they were drawn to what they had seen and encountered in the western and southern parts of Middle-earth. This caused them to separate into several different groups such as the Nandor who became Wood-elves of the Wilderland and later the Beleriand. Some of the Teleri who did not like the seas and partly due to the disappearance of Elwë in Nan Elmoth for a time, drew back and settled in the wooded areas of Region and Neldoreth that later became Doriath. The Teleri that were drawn to the sea settled along the western shores later becoming the Falathrim ruled by Círdan, who founded the coastal cities of Eglarest and Brithombar. Eventually, most of the Teleri went into the west.
Life in Aman
The elves that came to Aman were enriched by the knowledge of the Valar and the blissfulness of their lands and the elven clans developed their own cultures. The former ambassadors Ingwë of the Vanyar and Finwë of the Ñoldor became kings of their people and as Elwë never returned to Valinor, Olwë became Lord of the Teleri. The Vanyar were drawn to the Valar and the full light of the Two Trees and settled at the foot of Taniquetil with their king Ingwë, who became High King of the Elves revered by all elves living in the mountain below Manwë. The Ñoldor beloved by Aulë the Smith for their love of arts and crafts built the great city of Tirion on Túna where Finwë, the High King of the Ñoldor lived. The Teleri were drawn to sea and some never left the island ferry of Tol Eressëa until Olwë their lord who later built Alqualondë, with the help of the Ñoldor.
They developed writing and the arts of building, metallurgy, arts and crafts, and shipbuilding. Things like high culture, poetry, and many of the more subtle things were valued as well. For three ages, the elves lived in total peace and bliss wandering the lands and beautifying its glory. After three ages of imprisonment, Melkor completed his sentence and was released but his evil was not cured and he soon sought to poison the peace of Valinor. Taking a fair form, he sought to sow discontent between the elven clans. He offered his services to the elves but only the Ñoldor, desiring more knowledge were willing to listen to him. Wanting to possess their creations, he spread many lies amongst the House of Finwë making them suspect each other. This resulted in Fëanor threatening his half-brother Fingolfin. The Valar intervened and banished Fëanor from Valinor. The peace of the elves of Valinor was poisoned and as soon as Melkor was suspected he fled.
Twelve years later, Manwë. sought to heal the wounds between the Ñoldor at a festival held in Valmar, but Melkor and the giant spider Ungoliant destroyed the Two Trees, darkening Valinor, killing Finwë, stealing the three Silmarils of Fëanor, and fleeing to Middle-earth.
Revolt of Ñoldor and Return to Middle-earth
When the tragic death of his father became known, the wrath of Fëanor could no longer be contained. He gathered all the Ñoldor in Tirion and beneath the Tower of Mindon he urged the Ñoldor to return to Middle-earth in pursuit of Melkor and the Silmarils swearing an oath to war with Melkor now known as Morgoth. After being banned by the Valar for the rebellion and the violent deeds of the House of Fëanor, the Ñoldor elves returned to Middle-earth as exiles to face Morgoth and to establish and rule realms of their own.
The War of the Great Jewels
The crimes of Melkor in Aman and the subsequent rebellion of the Ñoldor started a centuries long war that would come to involve all the Elven kindreds of Middle-earth, and other races as well directly or indirectly. During this time, five great battles were fought against Morgoth and although many were victorious for the elves and their allies, the ultimate result was disastrous. Also, the doom that followed the Ñoldor as a result of the Kinslaying of Alqualondë first discovered by Thingol, King of Doriath and High King of the Sindar all but destroyed the relationship between the Sindar and the Ñoldor. There were also Middle-earth elves and other races such as the Petty-dwarves, that resented the exiled Ñoldor for usurping their rightful place in Middle-earth.
Though for hundreds of years, the Ñoldor elves fought and endured the forces of Morgoth with little military aid from the other Elven kindreds, a common fear and a common foe allowed for the elves (mostly the Ñoldor) to mingle with mortal Men and who recently came into the Beleriand from the east. The first were the faithful Three Houses of the Edain and the faithless Easterlings who mostly served Morgoth. At first only the Ñoldor had dealings with them as the other elves feared them, but over the generations men served the Ñoldor and gained their respect. After the Quest for the Silmaril, the blood the Eldar and the Edain mingled with each other first through the marriage of Beren and Lúthien and then through Tuor and Idril. This union would create a bond that would enrich and ennoble both kindreds from then to later ages.
The terrible Oath of Fëanor created strife between the Elven kindreds as even those not bound to it were drawn into it over the a Silmaril recovered by the man Beren and Thingol’s daughter Lúthien. The two brothers Celegorm and Curufin attempted to usurp the throne of Nargothrond after loss of Finrod in the Quest for the Silmaril, but were thwarted by the hound Huan and Orodreth and expelled. It was because of this deed that the Ñoldor of Nargothrond lent no aid to the Union of Maedhros during the Nirnaeth Arnoediad (Battle of Unnumbered Tears). Twice in the latter half of the First Age, the Sons tried to take the Silmaril from those who inherited it. These acts of cruelty and violence against their Elven kin caused great loss of life and resulted in the deaths of all of them except Maglor, who now wanders the coasts of Middle Earth singing about the suffering of the Noldor. Never again will he walk among Elves or Men.
Later Days and Decline
After the destruction of Beleriand in the War of Wrath, the remaining Ñoldor repented their rebellion and returned to Eldamar as well as many of the Sindar elves. The elves that chose to remain in Middle-earth founded peaceful realms. The Ñoldor lived in Lindon with Gil-galad, the High King of the Ñoldor, in Forlindon and hundreds of years later Celebrimbor, the last of the House of Fëanor founded Eregion (Hollin). The Sindar joined also with Gil-galad in Lindon and few went beyond the Misty Mountains into Wilderland, becoming leaders of the Silvan Elves in places such as Lothlórien and Greenwood the Great.
The Elven realms flourished for over one-thousand years until SA 1200 when Sauron under the guise of Annatar appeared out of the East, offering knowledge to the elves. Gil-galad mistrusted him and barred him from his kingdom. Sauron then approached Celebrimbor and the Elves of Eregion, and against Gil-galad's command they accepted him and his knowledge. With Annatar's help, Celebrimbor forged the Rings of Power, but Three Rings alone were made in secret by Celebrimbor and were not touched by Sauron's power. Then, Sauron forged The One Ring which was made to control the others but the elves were not fooled and took off their rings. Celebrimbor sent the ring Nenya to Galadriel and sent Vilya and Narya to Gil-galad in Lindon.
Furious that the elves had foiled his plans for domination, Sauron demanded the return of the rings and when they refused he prepared for war. For eight years Sauron laid waste to Middle-earth in his war against the elves but with help of the Númenóreans, the elves, led by Gil-galad, defeated him but the realm of Eregion was destroyed and Celebrimbor and his folk killed. Gil-galad then decided to abandon Eregion in favor of the new refuge of Imladris (Rivendell) formed at the foothills of the Misty Mountains and he made his herald, Elrond, the Lord of Imladris and his representative in Eriador. Lindon survived still as the greatest kingdom of elves in Middle Earth. The rest of the elves of Middle Earth that survived either moved to Lindon, sailed for the West, or continued to live in their lands under caution due to the continued threat from Sauron.
By the latter-half of the Second Age, Men continued to spread and grow in Middle-earth whether for good or ill. The Faithful from the Downfall of Númenór founded the great mannish kingdoms of Arnor and Gondor. Though Men were set to supplant them in Middle-earth, the elves were powerful and numerous enough to join with Men one last time to defeat Sauron. Gil-galad led the second greatest host of elves seen in Arda and formed the Last Alliance with Elendil, High King of all Dunedain, and vanquished Sauron in SA 3441.
With the Dominion of Men at hand, the elves became less numerous and more secluded with many becoming wearier of the now mortal lands. Only the realms of Lindon, Lothlorien, and Rivendell survived as havens of elven bliss. High Elves continued to live in Lindon but most sailed into the West after their king's death. The last of the High Elves left Middle Earth after the final defeat of Sauron in the War of the Ring.
Being immortal, Elves will continue to live in the world until its completion. Elves living in Aman live in a state of blissful happiness as they did before the Revolt of the Ñoldor. Elves that never chose to sail into Utter West instead choosing to remain in Middle-earth in places such as the Woodland Realm in the former Mirkwood, would probably become more and more secretive, less numerous, and hidden. It possible that due to their isolation and world weariness their bodies would eventually fade away into spirits roaming the forests until the end of time.
Elves, like Men, are both Children of Ilúvatar (God, The One) and thus are very similar to Men. Unlike Men, however, they are immortal, in that their bodies do not age once they have reached maturity, so that they do not seem to become elderly or die of old age, and they are not afflicted by disease. They can be killed by physical injury however, or they may come to death from wasting away if after long eons of life they lose the will to live. The Elves came into existence before Men, and when they die they pass to the Halls of Mandos in Valinor, where they await the end of Time.
Elves are (generally) unusually handsome of face and body, and they have far better vision and hearing than Men. They also have skills and abilities, and perception of things around them, far greater than that of Men, although whether this is an innate quality or is the result of long experience after having lived so long, is not known. They are also light of foot, can travel long distances without leaving tracks, and often can walk lightly across snow where the boots of Men would go through.