Page "Gondor" Paragraph 1

According to the narrative, Gondor was founded by brothers Isildur and Anárion, exiles from the downfallen island kingdom of Númenor, and along with Arnor in the north served as a last stronghold of the Men of the West.

After an early period of growth, Gondor gradually declined as the Third Age progressed, being continually weakened by the allies of the Dark Lord Sauron, and was only restored in dominance after his final defeat and the crowning of Aragorn.