At various points in history, the Realm of the Deepening Moon was a vassal of the elven empires of Aryvandaar, Shantel Othreier, and Illefarn. Circa -1,100 DR, Illefarn fragmented into three realms: Ardeep, Iliyanbruen, and Rilithar. At its height, Ardeep encompassed the lands between the Sword Mountains and the lower Delimbiyr Vale.
The rulers of Ardeep were known as laranlors (masculine) and laranlas (feminine), elven terms meaning regal lord and regal lady, respectively, and used to denote the king or queen of an elven vassal realm or minor kingdom. Laranla Fildaerae "the Night Flame" died in the Year of Ashen Faces (-395 DR) and was succeeded by her grandniece, Imdalace. When Laranla Imdalace disappeared in the Year of the Slaked Blade (4 DR), rulership of Ardeep passed to her kinswoman Embrae Aloevan. Laranla Aloevan became a Chosen of Mystra and Sehanine in the Year of Frostfires (292 DR). Shortly thereafter, in the Year of Promise (308 DR), she descended into madness and death, consumed by the silver fire of Mystra.
Aloevan's successor, Laranlor Ruardh Lightshiver, forged the Alliance of Illefarn with the shield dwarves of Dardath (now the Forlorn Hills) in the Year of the Cantobele Stalking (342 DR). In the Year of Trials Arcane (523 DR), this combined region became Phalorm, the Realm of Three Crowns. Ruardh ruled as the elf king of Phalorm until the Year of Melding (557 DR), when he fell against a horde of hobgoblins at the Battle of Blunted Fangs, near the site of present-day Dragonspear Castle. His successor, King Ellatharion, ruled until the Year of the Immured Imp (604 DR), when he vanished along with a contingent of elves and halflings last seen pursuing an orc horde into the High Forest. The last elf king of Phalorm (and hence Ardeep), Lathlaeril "Leafspear," died in the Year of the Jester's Smile (612 DR) at the Battle of Firetears, which was fought south of modern-day Triboar against the orcs of the illithid-led Everhorde. Sickened by the endless warring, most of Ardeep's moon elves abandoned Phalorm in the Year of the Lamia's Kiss (615 DR) and took ship to Evermeet.
The elven realm of Ardeep was refounded in the Year of the Curse (882 DR), when the area was resettled by moon elves from Eaerlann who had fled the demons erupting from Ascalhorn. The Alliance of Illefarn was briefly reborn as well, but the Eaerlanni elves quickly withdrew because of rising anti-human sentiment. The moon elves dwelt in quiet fellowship beneath the boughs until the Year of the Moonfall (1344 DR), when the last of the moon elves heeded the call of the Retreat and departed for Evermeet.