Gondor
Gondor is the great realm of Men in the south of Middle-earth, the chief kingdom of the Dúnedain, the Men of Numenor who survived the downfall of their island and founded realms in exile. Together with its sister kingdom Arnor in the north, Gondor was established by Isildur and his father Elendil at the end of the Second Age. Through the long Third Age, Gondor stood as the principal bulwark of the West against the power of Sauron in neighboring Mordor.
Gondor's capital is Minas Tirith, the White City, and its rulers in the years of the War of the Ring are the Stewards, who govern in the absence of a king. The realm's fortunes had waned over the centuries, but it remained the strongest kingdom of Men opposing the Dark Lord.
Geography
Gondor lies in the south, between the Misty Mountains' southern reaches and the sea, watered by the great river Anduin. Its heartland centers on the city of Minas Tirith and the fields of the Pelennor beneath it, with the White Mountains (the Ered Nimrais) rising to the west. To the east, across the Anduin, lies Ithilien, the fair garden-land bordering Mordor; to the south are the fiefs of Lebennin, Lossarnach, Dol Amroth, and others; and far south the haven of Pelargir on the Anduin.
The realm was once far larger, including Ithilien and the lands eastward, but its borders had retreated as its strength declined and the shadow of Mordor grew.
History
Gondor was founded by Elendil and his sons Isildur and Anárion, Faithful Numenoreans who escaped the Downfall of Numenor. With Arnor in the north, it formed the realms in exile. Isildur cut the One Ring from Sauron's hand at the end of the Second Age, but lost it and his life soon after. Through the Third Age Gondor knew great kings and grievous losses: the Kin-strife, the Great Plague, and wars with the Easterlings and the Corsairs. The line of kings failed, and the Ruling Stewards governed thereafter, awaiting the return of a king who long did not come.
In the story
In the War of the Ring, Gondor under the Steward Denethor bears the brunt of Sauron's assault. Boromir, Denethor's son, joins the Fellowship of the Ring; his brother Faramir defends Ithilien. The siege of Minas Tirith and the Battle of the Pelennor Fields are the great clash of the war in the south. Aragorn, heir of Isildur, comes at last to claim the crown, and with the destruction of the Ring and the fall of Sauron, the kingdom is restored under King Elessar.