This ancient pass, while hidden in a rugged and dangerous knot of mountains, had played an important role in the history of Harondor and Middle-earth. In the mid Second Age, it was through the Cirith Núrn (S. "Pass of Núrn") that Sauron's minions came south to establish his influence in Harad. Trade with the Haruzani realms and corrupt Númenóreans in Harnendor added to his store of lore and wealth;by the Third Age, the pass served as a conduit to lands farther South, from which originated the bulk of Mordor's trade with civilized peoples. After centuries of struggle, the Dark Lord's servants eventually drove the Gondorians from their southernmost territories and seized control of all of Near Harad. Both before and after this long campaign of conquest, the Dark Lord's messengers and warriors passed regularly through the Cirith Núrn.
The Cirith Núrn made the passage of the Caradhram, the southern Ephel Dúath, at its widest point, through the volcanic knot of mountains called the Garmagoum (Núr. "Big Smoke"). It was also the source of the headwaters of the Harnen, as numerous small mountain streams combined in the Cirith Núrn to form the great river.The largest of the source streams were both sweet and pure. The eastern half of the Garmagoum was, as the result of some cataclysm in the ancient past, thrust up and away from the western half. The defile formed by the rupture filled in with lava and shattered rock, but it still allowed cart and camel traffic to pass through the mountains any month of the year. The Cirith Núrn, while not the most dangerous of mountain passages, was certainly one of the most exotic and mysterious to the men of Gondor. It could be reached from the south from Oud Ilaz, along the, and ancient road called the Irit Núrn, from Harondor in the west along the Men Dirnen and dangerous mountain trails, and from the southeast from Deshgar (Har."Willow Home") in the Chelkar.
The Irit Núrn was the primary approach to the Cirith Núrn from the south. While not paved, it was quite passable as mountain roads went. At the mouth of the Cirith Núrn, just where the Irit Nurn climbed into the high peaks, there were mountain forests, flowered pastures, and no less than three active volcanoes in plain sight. All around the traveler lay eroded spires of reddish sandstone and twisted knots of black and grey lava rock. Sauron ordered a fortress built here soon after his disastrous war with the Elves and Númenór in the mid-Second Age, but it was an ill-starred place. Repeated earthquakes and volcanic eruptions left the structure looking rather squat when it was finished. In the twenty-fourth century of the Second Age, the Fortress Tegormaglûr (Núr."fearful smoking Tower) was put in the control of the Realm of Ard, ruled by the Riagwraith Adûnaphel. When she fled into Mordor after the surrender of Sauron in S.A. 3262. a volcanic eruption leveled Tegormaglûr and blocked the Cirith Núrn for almost a decade. The pass fared much better after the fall of Sauron in the War of the Last Alliance. The Tisgilm, a family of Haruzani fezirin sworn to the service of the Taskrals of Al Amrûn, built a new keep in the pass, further down the southern slopes.The Tisgilm dabbled in magic and were reputed to be somewhat mad, but they did well enough over the years, swearing allegiance to whichever Haruze power controlled the Rak Chelkar. Civilization in Núrn collapsed in the aftermath of Sauron's fall, so the Cirith Núrn was not nearly as important in the mid-Third Age as it had been in the Second. Nevertheless, when the last of the Tisgilm died mysteriously in T.A. 1091, an order of Gondorian knights sent a company out from Ithilien to takeover the Tisgilm keep and establish some rule of law in the area. No Haruze king dared quarrel with these interlopers so soon after the great victories of the Ship-kings, so the new Castle and monastery, Minas Airenaréva (Q. "Tower of Holy Fire"), stood virtually untroubled for five hundred years. This easternmost outpost of imperial Gondor never sided with Castamir the Ursurper during the Kin-strife. As an unimportant site on a distant frontier, Minas Airenaréva was forgotten by its founding empire. Its residents were eventually considered somewhat crazy: several of them had fallen into the habit of talking to the volcanoes that stood guard over the pass, and it was rumored among the superstitious that the mountains sometimes answered back. Not until T.A. 1650 did a Haruze king send an army to demand the surrender of Minas Airenaréva.The members of the order fought to the death and died in the flames of the tower's destruction. The Haruze built anew on the site of Minas Airenaréva, and their monarchs continued to have the rule of the place for the rest of the Third Age. With the passage of time these lords came more and more to be slaves of dark cults. The name of Tegormaglûr was given to the fortress again, and it became a fearful place. With the open rise of Sauron again in the late Third Age, the Cirith Núrn became a major road for the passage of soldiers and supplies into Mordor. It was said that Aragorn Elessar, during his years in Gondor when he was known as Thorongil, passed through the Cirith Núrn, but what he gained from this daring exploration is unclear. After the second fall of Sauron in T.A. 3019, both Núrn and Near-Harad became independent realms. The Cirith Núrn was no longer of great strategic importance; it became a path for peaceful commerce.
- MERP:Southern Gondor - The Land