Origins and Names
Finarfin's name in Quenya, the tongue of his birth, was Arafinwë, formed like his brothers' names upon their father's: Fëanáro and Nolofinwë stood behind Fëanor and Fingolfin in the same way. Finarfin is the form these names took as the history of the Noldor passed into telling among the Sindar and was set down in the surviving chronicles, and it is by this name, rather than the Quenya original, that he is generally remembered. Of the three sons of Finwë his is the plainest name, unmarked by later epithet or grim renown, fitting one whose part in the history of his people was chiefly one of restraint rather than deed.
He was the third and youngest son of Finwë, first King of the Noldor, and, unlike Fëanor, whose mother was Finwë's first wife Míriel, he was born of Finwë's second marriage, to Indis, a princess of the Vanyar. Fingolfin, his elder full brother, shared this same descent from Indis, so that Finarfin stood apart from Fëanor by blood as much as by temperament. Through his mother he and his line inherited hair of gold, the mark of the Vanyar, in visible contrast to the dark hair of the house descended from Finwë's first wife; this trait would pass down conspicuously among his own children in later generations.
That already-mixed inheritance was doubled when Finarfin took as his wife Eärwen, daughter of Olwë, king of the Teleri of Alqualondë: their children were thus heirs of Vanyar, Noldor, and Teleri alike, a threefold descent unmatched among Finwë's other grandchildren. Through this marriage Finarfin belonged by kinship to every one of the three kindreds of the Eldar who had made the journey to Aman, a distinction that set his household apart from the purely Noldorin-Vanyarin lines of his brothers.
History
In the untroubled years of the Two Trees, Finarfin's household in Tirion grew to five children: Finrod, Angrod, Aegnor, Orodreth, and a daughter, Galadriel. Of Finwë's three sons he was reckoned the fairest in voice and the gentlest in temper, and while Fëanor's restless craft and Fingolfin's steadfast pride shaped the outward history of the Noldor in these years, Finarfin's part was quieter, passed largely in the peace of his father's city rather than in deeds that were separately remembered.
That peace broke when Melkor's whispers set brother against brother; Fëanor, believing Fingolfin meant to supplant him, drew a blade against him before Finwë's throne, and for this was banished for a time from Tirion. When Finwë later died at Melkor's servant's hand and the Noldor were roused by Fëanor's grief and wrath to abandon Aman altogether, it was Finarfin who tried to check the fire spreading through the assembled people, speaking gently for restraint where his half-brother spoke for vengeance and flight. He was overruled: the greater part of the Noldor, including his own sons and his daughter, resolved to follow Fëanor into exile.
Finarfin nonetheless set out with the host, unwilling to be parted from his children, and so came with them to Alqualondë, the haven of Olwë's people. There Fëanor's demand for ships turned to violence, and the Teleri, kin to Finarfin through Eärwen, were slain in the first bloodshed among the Eldar. The kinslaying struck Finarfin doubly, as father of sons drawn into the fighting on one side and husband of a wife whose own people had died on the other, and it hardened his resolve against the flight he had never desired.
Before the host had gone much further north the Doom of Mandos was pronounced upon the rebel Noldor, naming the kinslaying and foretelling grief without end for those who persisted. At this, Finarfin turned back, and with him a part of the people who had marched thus far, while his sons and Galadriel chose to go on into exile under Fingolfin's following. He led the penitent back over the long road to Valinor, and there presented himself before the Valar to seek pardon for what had been done at Alqualondë, though he himself had taken no part in the slaying.
The Valar granted him and his followers forgiveness, and he was set to rule the Noldor who remained in Aman, holding Tirion upon Túna in the long years while Fingolfin bore the kingship of their exiled kindred in Middle-earth. Through that age he governed in the outward peace of Valinor, yet not untouched by grief, for word of his children's fortunes across the Sea reached him only slowly and often ill: of Angrod and Aegnor's deaths when Morgoth broke the Siege of Angband, of Finrod's end in the dungeons of Tol-in-Gaurhoth aiding Beren, and of Orodreth's fall in the ruin of Nargothrond.
When Eärendil's embassy at last moved the Valar to act against Morgoth, Finarfin, as king of the Noldor still dwelling in Aman, led his people forth in the great host summoned for the War of Wrath, the first and only time in the Elder Days that the Noldor of Valinor themselves went to war in Middle-earth. That war broke Morgoth's power and ended the First Age, and it closed the long separation between Finarfin's rule in Tirion and the fate of the kindred who had marched away under his brothers so many years before.
Role and Powers
Finarfin's authority was political rather than martial or magical: nowhere in the surviving accounts is he credited with feats of arms, craft, or lore to set beside those of his brothers or his own children. His standing rested instead on lineage and on the trust the Valar placed in him after the rebellion, and it was expressed chiefly through counsel and governance. As king of the Noldor who remained in or returned to Aman, he held a real but circumscribed dominion: he presided over a diminished people in Tirion, while the greater host of the Noldor, together with the title and burdens of leadership over them in Middle-earth, passed to his brother Fingolfin and, after him, to Fingolfin's own descendants. His kingship was thus a settled, largely ceremonial rule within Valinor rather than command over the exiled Noldor as a whole.
That authority was also conditional in a way his brothers' was not: it existed only because the Valar chose to pardon him and those who turned back with him, a forgiveness granted for restraint rather than earned through any deed of power. Even within his own household his word carried no compelling force, for his sons and his daughter judged for themselves and chose the road into exile against his wish to keep the family from harm; a father's counsel proved unable to hold his children back from a fate he could not share or later mend. Once the door to Middle-earth closed behind them, his rule gave him no means to protect or aid his children across the years that followed, and he learned of their trials and deaths only as report of them reached Aman.
His one recorded exercise of command in war came at its very end, when he led the Noldor of Valinor into the War of Wrath against Morgoth. Even there the text credits him with leadership of the host rather than with any personal feat comparable to Fingolfin's challenge to Morgoth or Fëanor's death in battle; his part was that of a king marshalling his people for a cause resolved by the Valar, not that of a warrior remembered for his own hand. In this his role stands apart from those of his siblings and children: where their power in the tales is measured in individual deeds, sacrifices, or losses, his lies in the steadier, less dramatic exercise of stewardship, sustained across the long years in which Aman itself saw no war.
Relationships
Among Finwë's three sons, Finarfin's closest bond was with Fingolfin, his brother in full blood through Indis, a kinship distinct from the half-kinship that joined all three but bound only these two by shared descent on both sides. Fëanor's long mistrust of his father's second family fastened chiefly upon Fingolfin, whom he suspected of scheming for the crown; the tales record no comparable suspicion falling on Finarfin, whose youth and gentler temper seem to have placed him outside that particular rivalry. It was this standing apart from the quarrel, trusted by neither brother as an ally against the other, that let him step between them when Fëanor drew a blade before Finwë's throne, though his intervention could calm the moment without touching the enmity beneath it.
His marriage to Eärwen made Finarfin's own household the single point at which the three kindreds of the Eldar in Aman were joined by blood rather than by treaty or alliance alone. Nothing in the surviving account suggests that the grief of Alqualondë ever broke this union: Eärwen is nowhere recorded as parted from him, and the court he kept in Tirion after his pardon continued to hold Noldorin and Telerin kinship together even as war had opened, far off in Middle-earth, between the wider kindreds of his sons and her own people. It is a bond the sources report only by its outcome and never its texture, yet its endurance through the very event most likely to have broken it marks it as unlike any other marriage among Finwë's descendants.
Among his own children, the bond formed under Finarfin's roof in Tirion outlasted the parting from him: Angrod and Aegnor held the northern march of Dorthonion together as joint wardens for as long as the siege of Angband endured, and it was Orodreth who succeeded his elder brother Finrod as lord of Nargothrond when that charge passed from him. Scattered across Beleriand and answering in the end to their uncle Fingolfin's house rather than to their own father, Finarfin's five children nonetheless went on acting as a family bound by more than shared blood, a cohesion that had evidently taken shape long before any of them had cause to leave Aman at all.
Drafts and Variants
For most of the long gestation of the legendarium the name later fixed as Finarfin belonged to a different figure. In the earlier prose accounts of the mythology and in the accompanying genealogies and etymological notes, the third son of Finwë was called Finrod, while the name now attached to his own eldest son, the founder of Nargothrond, was Inglor. Under this older scheme it was Finrod, not Finarfin, who married Eärwen, counselled against the flight of the Noldor, and turned back after the Doom of Mandos, and it was Inglor who later took Felagund as a further name. This arrangement held through the successive prose Quentas and their attendant king-lists and name-lists across a long stretch of the legendarium's development.
Only late, in the revision of the material undertaken after The Lord of the Rings was largely complete, did Tolkien exchange the names, giving the father the new form Finarfin and passing Finrod, now joined to Felagund, to the son. Christopher Tolkien traces this swap and its consequences for the genealogies and indices of the later Silmarillion materials, noting the difficulty it caused in reconciling earlier texts, where every occurrence of Finrod as the father's name had in principle to be understood as referring to the figure who would become Finarfin. The change was made too late to be carried consistently through all of Tolkien's own working papers, so that the identity of the two names remains, in the published History of Middle-earth, a matter Christopher Tolkien has to gloss rather than one Tolkien himself ever fully regularized.