The fate of the kingdoms, especially that of Gondor, would come to dominate the history of the Third Age.
Geography
During Aragorn's reign, the Reunited Kingdom expanded to retake all territories that had originally belonged to both Arnor and Gondor at their greatest extents, excluding only Rohan (the grant of which he renewed), the Shire, and the Drúadan Forest, which governed themselves while being under the protection of the High King.
The Reunited Kingdom included all the lands of Arnor; all of Eriador, except the regions beyond the Lune and the lands east of Greyflood and Loudwater, in which lay Rivendell and Eregion.
In Gondor, the realm extended:
- North to the Mouths of Entwash and the southern eaves of Mirkwood
- West to the Greyflood
- East to the inland Sea of Rhûn
- South to the River Harnen, and also along the coast to the peninsula and haven of Umbar
Allied states of the Reunited Kingdom included Rohan, (possibly) Mordor (when it was under the rule of the Men of Nurn), Dale, Erebor, the Glittering Caves (under Gimli's rule there, and possibly his sucessors), East Lorien, Beorning territory, the Shire, the Treegarth of Ornthac (Ent territory), Druadan Forest (home of the Wild Men, who were given autonomy by Aragorn) and the Woodland Realm
History
Background
At the end of the Second Age, Elendil and his sons established two great kingdoms in Middle-earth: Arnor in the north and Gondor in the south. These Kingdoms of the Dúnedain were united under a single High King, Elendil himself, who ruled the North-kingdom while his sons reigned jointly over the South-kingdom.
In the first years of the Third Age, this union failed. After the loss of Isildur at the Disaster of the Gladden Fields, his nephew Meneldil took up the kingship of Gondor, and that country remained independent from the North-kingdom through most of the Third Age.
Dissolutions
In the north, the realm of Arnor fell into troubled times. It broke into three separate kingdoms, and in time these too were lost, so that the Dúnedain of the North-kingdom of Elendil were reduced to a wandering people led by a Chieftain. Nonetheless, they were able to maintain Isildur's line in unbroken descent.
However, the House of Anárion failed in Gondor when Eärnur was lost without heirs. Its rule was taken up by the Stewards.
There were two attempts to reunite the kingdoms. The first of these occurred in TA 1944 when Arvedui of Arthedain claimed the High Kingship of the Two Kingdoms. His claim was rejected by Steward Pelendur and the Council of Gondor, who elected to maintain their independence.
Reunification and Later History
More than a thousand years later, after the War of the Ring, Arvedui's direct descendant, Aragorn II, came forward to make the same claim. This time, the people of Gondor accepted a High King, and the Two Kingdoms were reunited at last.
Aragorn restored Osgiliath and re-peopled it, but retained Minas Tirith as the chief city. He rebuilt Annúminas and when he went north, would rule from there. He also had the ruins of Fornost Erain rebuilt and made it a great city where Men dwelt once again. the Shire was an exception to this, and though it lay within the Reunited Kingdom, Aragorn made a law that Men should not enter it without permission , a law that he observed himself.
During his reign, he, alongside King Éomer, led military campaigns beyond the Sea of Rhûn and on the far fields of the South. As a result, he was able to re-establish his dominance in places which Gondor initially held at the height of its power. The threat of the Corsairs was finally completely subdued during his reign and Umbar was finally re-taken. He also made peace with the Haradrim after his coronation.
After Aragorn's death in FO 120, his son Eldarion took up the high kingship. One hundred years into his reign, a dark cult emerged in Gondor, but was overthrown soon after it was discovered.
It was foretold that after Eldarion's kingship ended, the Reunited Kingdom would last for at least "a hundred generations" before a new age began and Eldarion's descendants would be kings of many realms in days long after. While it is untold whether or not this prophecy was true, Gondor, Arnor, and the chronicles of the House of Telcontar eventually became lost to time.