The city's wealth was founded on its mines, which produced mithril, a fictional metal of great beauty and strength, suitable for armour.

The Dwarves dug too greedily and too deep for mithril, and disturbed a demon of great power: a Balrog, which destroyed their kingdom.

Scholars have identified likely sources for Tolkien's Moria: he had studied a Latin inscription about a lost ring at the temple of Nodens in Gloucestershire, at a place called Dwarf's Hill full of old mine-workings.

The West Gate that the Watcher in the Water crashes closed behind the Fellowship recalled to commentators the Wandering Rocks of Greek mythology, and Odysseus's passage between the devouring Scylla and the whirlpool Charybdis.

[T 2] Moria was originally a system of natural caves located in Dimrill Dale, a valley on the eastern side of the Misty Mountains.

The caves of Moria, where the Dwarf city-kingdom of Khazad-dûm was founded, were situated under Silvertine; their mouth overlooked Dimrill Dale, which contained many waterfalls and a long, oval lake that reflected stars even in daylight.

Perceiving these stars as a crown glittering above his head, Durin took this as an auspicious sign, named the lake Kheled-zâram, the Mirrormere, and chose the eastward-facing caves above it for his new stronghold.

[T 2] Far below even the deepest mines of the Dwarves lay a primordial underworld of tunnels, streams and lakes in perpetual darkness, inhabited by primitive creatures.

The tunnels were "gnawed by nameless things" from the beginnings of Arda,[T 6] and, as Gandalf suggested, from this underworld the Watcher in the Water may have emerged.

Celebrimbor, the Lord of Eregion, used ithildin lettering on this gate on behalf of its builder, his friend the dwarf smith Narvi.

[T 10] In the Third Age, the more easily accessible seams of mithril were exhausted, and the Dwarves dug deeper until they disturbed a Balrog, a powerful fire-demon.

Thrór, the heir of the Dwarf-kings of Khazad-dûm, attempted to enter his people's ancestral home, and was killed by Azog.

Dáin refused, sending Glóin and his son Gimli to the Council of Elrond, starting the quest of the Fellowship of the Ring.

[T 12] He led his people back to Khazad-dûm, where they remained "until the world grew old and the Dwarves failed and the days of Durin's race were ended".

Every level consisted of a network of arched passages, chambers and many-pillared halls, often with "black walls, polished and smooth as glass".

[T 6] During the kingdom of Khazad-dûm, the subterranean realm was "full of light and splendour", illuminated by many "shining lamps of crystal".

The J. R. R. Tolkien Encyclopedia notes that Middle-earth gates are important both symbolically and practically: "They mark exclusion or admission.

They were however decorated with designs engraved in ithildin made by the elf-Lord Celebrimbor of Eregion and the dwarf Narvi from mithril mined in Moria.

Tolkien's drawing of the designs on the Doors of Durin was the only illustration in The Lord of the Rings during his lifetime (other than cover-art and calligraphy).

The inscription was in the Elvish language of Sindarin, using the Tengwar script;[3] Gandalf translates it as "The Doors of Durin, Lord of Moria.

"[T 13] Scholars have commented that "Moria", an unfriendly Elvish description meaning "The Black Pit", was hardly how a ruler of Khazad-Dûm would choose to describe his realm; and that since the name was not used until the Balrog was awakened in the Third Age, it was also anachronistic.

Tolkien later recalled that the name was "a casual 'echo' of Soria Moria Castle in one of the Scandinavian tales translated by Dasent.

[1] A historic source is the Poetic Edda, with which Tolkien was familiar; the protagonist in the Skírnismál notes that his quest will involve misty mountains, orcs, and giants.

[10] The Tolkien scholar Jane Chance observes that the fall of the dwarves, first those of Durin, then those of Balin, is brought about through avarice, their greed for Moria's deeply-buried mithril.

[15][16][17] The professor of English literature Sue Zlosnik notes that the fantasy world in Tolkien's invented mythology for England[18] is constructed with elaborate detail.

[18] Erin Derwin, writing in The Artifice, compares the fellowship's time in Moria with Siegfried Sassoon's First World War poem "The Rear-Guard", in which he describes "groping along the tunnel" in a labyrinth of dark trenches, with "muttering creatures underground", recalling, Derwin suggests, the awakening of the Orcs and the Balrog by the hobbit Pippin.

[19] The scholar of English literature Charles A. Huttar compares this "clashing gate" that crashed shut behind the travellers to the Wandering Rocks that in Greek mythology lie near the opening of the underworld, Hades, and, along with the monstrous Watcher in the Water, to Odysseus's passage between the devouring Scylla and the whirlpool Charybdis.

[20][21] Tolkien was asked whether the name Moria meant the biblical mountains of Moriah, where Abraham was to sacrifice his son, Isaac.

Tolkien wrote that his mind did not work that way, explaining that Moria meant "Black Chasm" in Sindarin, the root Mor occurring in Mordor, Morgoth, Morgul.

The movement is split into two sections, "The Mines of Moria" and "The Bridge of Khazad-dûm", and it depicts the events that take place there in The Fellowship of the Ring (novel).