Our best evidence shows Isildur as being born in the year II 3209, at a time when the FaithfulKingTar-Palantir ruled Númenor. Isildur's family were hereditary Lords of Andúnië, and at that time close counsellors of the King. Thus Isildur grew up in a time of hope and prosperity, but this was not to last. In II 3255, when Isildur was forty-six years old, Tar-Palantir died and his throne was usurped by his unscrupulous nephew Ar-Pharazôn.
Within just a few years after his ascension to the Sceptre, Ar-Pharazôn launched a war against a being in Middle-earth who claimed to be its ruler. This was Sauron, and powerful as that Dark Lord had grown during the Second Age, he could not hope to challenge Ar-Pharazôn's military might. Sauron allowed himself, therefore, to be carried as a hostage back to Númenor, where he began to exert growing influence over the counsellors to the King. Eventually, Isildur's grandfather Amandil was the only remaining counsellor who would not turn to Sauron's side, and so Amandil found himself expelled from the Council of the Sceptre.
After Amandil was dismissed from the Council, he withdrew to Rómenna, the main stronghold of the Faithful in Númenor. He called his family and followers to attend him there, and as a prominent member of that group, we can assume that Isildur went to Rómenna at this time. Amandil had heard that Sauron intended to sacrifice the White Tree that had grown in the courts of Armenelos through Númenor's long history, and Isildur became determined the save it.
Isildur travelled to Armenelos and, disguising himself, crept into the courts where the White Tree stood. He stole a fruit from the tree, but the guard was roused and he was forced to fight his way out. Desperately wounded, he escaped back to Rómenna before he succumbed to his injuries. Autumn passed into winter, and winter into spring, but as the seed of the White Tree sprouted Isildur was healed of the wounds he had received in its rescue.
Now dark days descended on the Faithful. The White Tree was burnt as a sacrifice, as were many of the Faithful themselves, in a great temple constructed by Sauron. Amandil discovered that, urged on by Sauron, Ar-Pharazôn was planning to attack Aman itself. Hoping to prevent the disaster this would cause, Amandil laid plans of his own: he would travel into the West as an emissary to the Valar. Before he set sail, he arranged for his family to depart from Númenor themselves, and take ship into the seas to the east. Of the ships in their small fleet, Isildur commanded three, and aboard his own vessel was the seedling of Nimloth the lost White Tree. Also aboard these ships was Isildur's young son Elendur, his only child at this time.
Isildur and the rest of Elendil's family waited aboard their ships off the eastern coasts of Númenor, while Ar-Pharazôn set out to break the Ban of the Valar and sail into the West. Thirty-nine days passed, and suddenly the Sea rose with an overwhelming force. Ar-Pharazôn's pride had triggered a terrible response, and the entire land of Númenor was consumed by the Great Sea. The ships of Isildur and his people were driven before a great wave that carried them eastward across the ocean.
Isildur's ships, along with those of his brother Anárion, were swept southwards and eastwards by the raging ocean. At last they reached the shores of Middle-earth, and sailed up the wide Mouths of Anduin, on whose banks the Faithful settlement of Pelargir stood.
As the heirs of the rightful Lord of Andúnië, and therefore of royal Númenórean blood, Isildur and Anárion were accepted as rulers by the Faithful who dwelt in the region, and they founded a new realm around the Mouths of Anduin. Meanwhile, their father Elendil had also survived, but had landed far to the north. The brothers acknowledged his overlordship as High King in Middle-earth, while jointly ruling their new kingdom in his name.
The brothers began to build, constructing magnificent cities across their new land. On Anduin they made Osgiliath, which would be the capital of the realm, in which their two thrones stood side by side. They raised other remarkable works, including the tower of Angrenost to guard the western approaches of the land. This building of extraordinary cities and towers gave the new country its name: Gondor, the land of stone. On a hill in the far interior of the new land, Isildur set a great black stone, the Stone of Erech, which he had brought out of the lost isle of Númenor.
Among these other mighty works, the brothers Isildur and Anárion each made a tower for themselves. For Isildur this was Minas Ithil, named, like its builder, for the Moon. It was constructed in the land of Ithilien (which also took its name from the Moon), in the foothills of Ephel Dúath at the mouth of a narrow pass leading into the now-deserted land of Mordor. It was there that Isildur planted the seedling that had grown from the fruit of the White Tree of Númenor. Also in this Tower of the Moon he kept one of the palantíri that he had brought out of the wreck of Númenor.
At the time he landed in Middle-earth, Isildur had just a single son and heir, Elendur. Over the years the followed, three more sons would be born: Aratan, Ciryon and Valandil. The youngest of these, Valandil, was born into a time of turmoil, when the peace that Isildur and his people thought to have found in Middle-earth came to an abrupt and devastating end.
War Rekindled
Sauron had been in Númenor when it fell, and his body was destroyed in the Downfall, but his spirit returned to Mordor, where he began to lay plans against the Exiles of Númenor. The great Fire-mountain in the midst of his realm, eastward beyond the mountains from Isildur's fortress of Minas Ithil, burst into sudden flame, and the Gondorians began to prepare for an assault out of Mordor.2
In II 3429, a little over a century after the foundation of Gondor, came the inevitable attack by the Dark Lord. Lying as it did on the borders of the Black Land, Minas Ithil was Sauron's natural first target. The Dark Lord's forces captured the city and burned the White Tree in Isildur's courts, but Isildur himself was able to escape. With his wife and sons, and with a seedling of the precious White Tree, he took ship down the Great River to its Mouths, and then sailed northward along the coasts of Middle-earth to seek his father Elendil in Arnor.
Once Isildur reached his father the High King with news of Sauron's attack, Elendil joined with his friend and ally Gil-galad, and together the two created a great Alliance. A huge force of Elves and Men was gathered from across Middle-earth and marched southwards, planning to end the threat of the Dark Lord for all time. Isildur travelled southward as part of the Alliance, crossing the Misty Mountains with his followers and approaching the Gates of Mordor.
The first engagement of the conflict was the Battle of Dagorlad, an immense and bloody battle fought across the lands northward of the Morannon, in which Sauron's forces were finally driven back into Mordor. (We're not told specifically that Isildur fought in this battle, but as one of the main commanders of the Last Alliance, it seems safe to assume that he was present for its first and most decisive action.) The armies of the Last Alliance then marched on Sauron in Barad-dûr within Mordor, setting the Siege of Barad-dûr that would last for seven years.
During the War, Isildur sent his sons Aratan and Ciryon to hold Minas Ithil and guard the westward ways out of Mordor, to prevent any possible escape by Sauron through Ephel Dúath. Isildur himself took part in the Siege of Barad-dûr, and he was accompanied by Elendur, his eldest son and heir. (Isildur's fourth son Valandil was a mere child at this time, and remained safely in faraway Rivendell.) It was in the sixth year of the Siege that Isildur lost his brother: Anárion was slain when a great stone thrown from the heights of the Dark Tower struck him on the head.
After seven years of siege, Sauron agreed to decide the outcome of the War in single combat, and met the commanders of the Last Alliance on the slopes of Mount Doom. There he fought Elendil and Gil-galad, and both were slain, but the Dark Lord was also cut down. Isildur was there to witness the death of his father and the Fall of Sauron, and after the combat he cut the Ruling Ring from the finger of the defeated Enemy.3
The Ring blazed with heat when Sauron wore it, and Isildur himself was dreadfully burned when he picked it up, though it quickly cooled. The combat had taken place on Mount Doom where the Ring had been forged, so Isildur could easily have destroyed it at that time, and both Elrond and Círdan urgently counselled him to do so. Isildur refused, instead taking and keeping the Ring as a weregild4 for his dead father and brother (or at least so he claimed, though doubtless the lure of the Ring was already at work on him). Soon afterward, Isildur made a record of these events (a document later known as the Scroll of Isildur) which he deposited in the archives of the South-kingdom.
A Brief Peace
With the loss of his father and his brother in the War, Isildur was now undisputed High King of the realms of the Dúnedain. After Sauron's defeat he went to Minas Anor, the tower built by his brother Anárion, and planted the seedling of the White Tree in the courts of that city. This line of trees would continue to grow there for nearly three thousand years (and the line would be resumed after the War of the Ring to continue into the Fourth Age).
As the new High King, the seat of Isildur was now at Annúminas in the distant North-kingdom. Before setting out for the North, however, Isildur spent two years in Gondor, ordering the realm and setting its borders. During this time he travelled around the South-kingdom, and found a secret hallow on the hill of Eilenaer (later known as the Halifirien) near the centre of the land. There he laid his father Elendil to rest, and established a Tradition whereby the secret of Elendil'sTomb would be preserved by the Kings (and later the Stewards) of Gondor).
Isildur chose a King to rule the South-kingdom in his name, as he had ruled it under his father Elendil. For this role he selected his nephew Meneldil, a son of Isildur's slain brother Anárion,5 and part of Isildur's reason for remaining in the South for so long was to train Meneldil in the ways of kingship. With Meneldil installed as King of Gondor, and his affairs in Gondor arranged as he wished, Isildur gathered his men and his three elder sons and set out on the long northward march to Arnor.
The main body of Isildur's army had already travelled to the North-kingdom, so it was with but a small force of some two hundred troops that he rode from Osgiliath in the month of Ivanneth (modern September) of the year III 2. He planned to march through the Vales of Anduin on the eastern side of the river, then cross it and pass westward, eventually reaching Imladris (where his youngest son Valandil was under Elrond's protection) before moving on to Annúminas on the shores of the lake of Nenuial.
For thirty days, Isildur and his companions marched northward without incident. Anduin at this time was swollen with rainwater, and so the Dúnedain moved upslope, travelling along the eastern edge of Anduin'sVale. By sunset on the thirtieth day they were marching past Greenwood the Great, opposite the Gladden Fields, and their path carried them close to the dense trees.
As the Dúnedain approached the end of the day's march,6 a horde of Orcs emerged suddenly from the trees and set upon them. Having thought the creatures of Sauron all vanquished in the War, Isildur and his small force of Men were utterly unprepared for this attack. Isildur quickly arrayed his Men, and entrusted the Shards of Narsil to his squire Ohtar, telling him to flee with them back to Rivendell. Isildur's Men found themselves outnumbered more than five to one, and though the Dúnedain fought bravely, almost all of the two hundred fell to the Orcs, including Isildur's three elder sons.
In desperation, Isildur took the Ring that he carried and endured the pain of putting it on his finger. He had not the strength or knowledge to use it to command the Orcs, but it did make him invisible even to their keen eyes.7 Scrambling away from the carnage, Isildur made his way downslope, westward towards the swollen river Anduin. An attempt to cross the raging torrent seemed hopeless, but having no other choice, Isildur cast off his armour and entered Anduin's rushing waters.
As Isildur laboured to swim across the Great River, its current swept him southwards, so that when at last he reached the western bank, he had been carried far into the Gladden Fields. As he struggled ashore he discovered that the Ring was gone: it had betrayed him,8 and slipped from his finger into Anduin as he made the crossing. He was overwhelmed by a sense of loss, but also of relief to be free of its influence.
Isildur had left his enemies far behind on the eastern banks of Anduin, but he was not yet safe. The Orc-band that had attacked his Men had come down originally from the Misty Mountains to the west, and more Orcs waited for him on the western bank. In abandoning Isildur, the Ring had left him visible to his enemies (and so, among its many other names, it came to be known as Isildur's Bane). The Orcs that lay in wait in the Gladden Fields therefore discovered Isildur and shot him down with their poisoned arrows. So Isildur's life ended, having ruled as High King for just two years, and never having reached his Northern throne.
The Aftermath
Isildur's sudden demise would have far-reaching effects on the history of Middle-earth. The High King who should have led the united Dúnedain in Middle-earth had fallen, and, even more importantly, the Ruling Ring of Sauron was lost.
The Ring sank into the mud at the bottom of the Great River, its fate unknown to any in Middle-earth at that time. It would remain hidden there for nearly two and a half thousand years, until it was discovered by a Hobbit-like creature named Déagol, then claimed by another of the same kind, Sméagol, who carried it far from Anduin. So, even when Isildur's fate was discovered, and the area of his death was searched for the Ring, the searchers discovered nothing. At least, they did not find the Ring, though it seems that Saruman's servants found the remains of Isildur himself (after the War of the Ring, the Elendilmir, the royal jewel that Isildur had worn, was discovered in Saruman's vaults).
One of the most immediate effects of Isildur's death was the division of the Kingdoms of the Dúnedain. Isildur had assigned his nephew Meneldil to rule Gondor in his name, but now Meneldil became sole King of Gondor, and his descendants continued to rule the South-kingdom as an independent nation. Meanwhile in the North, the new King of Arnor was Isildur's only surviving son, thirteen-year-old Valandil (though in fact he did not formally take up his rule until he reached his majority in III 10).
Though the line of descent from Isildur remained unbroken in the North, the kingdoms ruled by Isildur's descendants did not survive the Third Age. Indeed, it was less than a thousand years before Arnor ceased to exist, breaking into three smaller kingdoms of which one, Arthedain, was ruled by the elder line of Isildur's Heirs. These lesser kingdoms found themselves at war with the Witch-king of Angmar, and one by one they fell. By the end of the Third Age, the Dúnedain of Arnor had been reduced to wandering Rangers led by a Chieftain, a title held by Aragorn at the time of the War of the Ring.
If Isildur had lived, the South-kingdom of Gondor would have remained a vassal state under his High Kingship. Indeed, even if he had left a strong heir this situation might have continued, but all three of Isildur's adult sons were lost with him in battle. The only viable heir was a young child far away from Gondor, and so Meneldil took up the mantle of an independent King. His descendants would rule the South-kingdom as a separate realm for more than two millennia, and after the last of the Kings was lost, its independent tradition would continue under the Ruling Stewards.
Isildur left more tangible legacies in Middle-earth than his bloodline. The White Tree that he had planted in Minas Anor continued to thrive for more than sixteen hundred years, and its offspring lived for a further twelve hundred years or more. When the second tree died in III 2872, it had no seedling and was left standing as the Dead Tree, but after the War of the Ring another seedling was found. So the line of the White Trees of Minas Tirith, descended from a fruit rescued in Númenor by Isildur long before, continued into the Fourth Age.
Isildur's great tower of Minas Ithil still stood on the borders of Mordor, and remained an important outpost of Gondor for two millennia after Isildur's time. In III 2002, it was once again captured by Mordor as it had been during Isildur's own lifetime, but this time Gondor had no power to recapture it. Instead it became Minas Morgul under the power of the Nazgûl. The palantír that it held - Isildur's own Seeing-stone - thus fell into the clutches of the Dark Lord.
Far from Minas Ithil, within and beneath the White Mountains, Isildur left a ghostly horde, the Men of the Mountains who had failed to submit to his command in the War of the Last Alliance. Cursed for breaking the oath they had made on the Stone of Erech, these Dead Men were doomed to wander the Paths of the Dead, and there they remained throughout the more than three thousand years of the Third Age. Eventually, Isildur's direct descendant Aragorn came to them for aid in the War of the Ring, and they finally fulfilled their oath and were released. Their aid proved crucial, and so, if not for Isildur's curse made an Age beforehand, Minas Tirith might very well have been lost to the Enemy.
Statues of Isildur were to be found across the South-kingdom, most notably within the throne room of Gondor beneath the White Tower in Minas Tirith. For sheer size, the greatest of these was made to mark the northern border of the realm, where immense statues of Isildur and his brother Anárion were set looking northward on either side of the course of Anduin. Together these statues formed the Argonath, the Pillars of the Kings that guarded the way down Great River into Gondor. In later years the borders of Isildur's realm contracted, leaving his great stone form standing far beyond the true northern limits of the South-kingdom.
Among the Dúnedain, little was known of Isildur's end. Besides Ohtar, two others survived the assault, and from their accounts it was known that Isildur had fled the Orcs, and that he had been slain - by an Orc-arrow, it was presumed. The Wise were able to divine that he had carried the Ring with him and lost it in Anduin, but even this knowledge did not find its way to Gondor. There was a certain irony, then, in the fact that the clue to confirm the Ring's return was secretly held in the deep vaults of Minas Tirith. There, Isildur had left a Scroll that detailed his experiences with the Ring. That account enabled the WizardsSaruman and Gandalf to separately deduce its fate, and for Gandalf to identify it when it was found again.
As the Third Age had passed, and the realms of Arnor and Arthedain were lost, the line of Isildur was almost forgotten. Among some of those who did remember Isildur's legacy, such as Denethor of Gondor, Isildur's heirs were openly mocked, but others remembered Isildur differently. Sauron himself, who had seen Isildur with his own eyes on Mount Doom, feared Isildur's descendant Aragorn when he showed himself to the Dark Lord through a palantír. After the War of the Ring, the people of Gondor were more accepting of the Heir of Isildur than their lord Denethor had been, and took Aragorn as their new King. So, after more than three thousand years since Isildur's loss, his direct descendant once again became High King of the Dúnedain in Middle-earth.
Notes
1
The date of Isildur's birth appears only in The History of Middle-earth volume XII, The Peoples of Middle-earth. It cannot therefore be considered completely reliable.
2
It was apparently at this time that Isildur called on the aid of the Men of the Mountains ('...when Sauron returned and grew in might again' - The Return of the King V 2, The Passing of the Grey Company). They had sworn allegiance to the Gondorians, but they ultimately refused to go to war and were cursed by Isildur. The curse proved remarkably effective, leaving them to wander the Paths of the Dead through the next age of the world.
3
We don't have a detailed account of Isildur's part in the combat on Mount Doom, but some sources suggest that he did more than simply watch the fight take place. After the event, he's recorded as claiming to have actually killed Sauron ('Was it not I that dealt the Enemy his death-blow?', he says in Of the Rings of Power and the Third Age). This seems to be a reference to his ending the life of an already-defeated Enemy (presumably by the action of taking the Ring), though admittedly the text is open to interpretation.
4
In the Anglo-Saxon justice system, a weregild or 'man price' was a financial penalty made to compensate for murder or other damage. So, in taking the Ring as a weregild, Isildur was effectively taking a payment from Sauron to compensate for the deaths of his father Elendil and his brother Anárion.
5
When Elendil had ruled as High King, he had assigned the South-kingdom to be ruled jointly between his sons, and if Isildur had followed the same arrangement, then his own sons would have shared the Kingship of Gondor. He certainly had this option: we know that his three elder sons, Elendur, Aratan and Ciryon, were all with him in Gondor after the War of the Last Alliance. It is not explained why Isildur instead chose Meneldil to rule Gondor rather than his own sons, but it proved to be a decision that had far-reaching effects across the history of Third Age.
6
Accounts differ regarding the exact disposition of Isildur's forces at the time of the Orc attack. In Of the Rings of Power and the Third Age in The Silmarillion, it's said that Isildur had actually made camp but, anticipating no danger, had failed to post a guard. In the much more detailed account of The Disaster of the Gladden Fields in Unfinished Tales, however, it's stated that the Dúnedain were still on the march, though nearing the point where they would set up camp.
7
According to some accounts, the Ring did not make Isildur completely invisible. The Elendilmir, the shining jewel that he wore on his forehead as the symbol of his High Kingship, still shone brightly even though Isildur wore the Ring. In this version of events, Isildur had to pull down his hood to hide the gleaming light. It is not explained how the Elendilmir was - almost uniquely - able to resist the Ring's power of invisibility (nor indeed why Isildur didn't simply take it off).
8
The use of the word 'betrayed' here follows multiple sources that imply that the Ring in some sense 'wanted' to leave Isildur. For instance, at the Council of Elrond, Elrond says of the Ring that '...soon [Isildur] was betrayed by it to his death...' (The Fellowship of the Ring II 2, The Council of Elrond). Thus the Ring seems to have had at least some sense of volition of its own. Remaining in the possession of the Dúnedain gave it no way of returning to its maker, and so it abandoned Isildur and waited to be found by a more suitable bearer. Exactly how much volition we can assign the Ring is far from clear, but it seems to have been able make at least simple decisions for itself. As Gandalf says of a later Ring-bearer, Gollum, it was '...the Ring itself that decided things. The Ring left him' (The Fellowship of the Ring I 2, The Shadow of the Past).