Narmacil I, son of Atanatar II Alcarin, inherited the Kingship of Gondor when the South-kingdom was at the height of its power and wealth. He was not a great King, and indeed soon tired of the role. In III 1240, after just fourteen years on the throne, he turned over the rule of Gondor to his nephew Minalcar, who ruled as Regent through the rest of Narmacil's titular Kingship.
Narmacil's Regent Minalcar was a powerful and energetic Man, who routed the armies of the Easterlings, fortified the borders of Gondor and actively pursued diplomacy with Gondor's neighbouring tribes. It is not recorded, though, that his uncle King Narmacil had any hand in any of Minalcar's great endeavours. Narmacil, in fact, is chiefly remembered as being Gondor's second childless King, the first having been Tarannon Falastur in the tenth century.
Narmacil I sat on the throne of Gondor for sixty-eight years, but for fifty-four of these years Minalcar ruled Gondor as Regent. Narmacil died childless, and was succeeded by his younger brother Calmacil.