Thrain

Thrain is a dwarf of the royal line of Durin, the son of Thror, the King under the Mountain, and the father of Thorin Oakenshield. His life was defined by the catastrophic loss of the dwarves' ancient home beneath the Lonely Mountain to the dragon Smaug. After Smaug's attack, Thrain and his father Thror escaped with singed beards, but they were driven into exile, forced to earn a living as best they could, often sinking as low as blacksmith-work or coalmining. Thrain's subsequent fate became a mystery that haunted his son for a century.

Disappearance and Imprisonment

Thrain went away on the twenty-first of April, a hundred years before the events of the story, and was never seen by his son Thorin again. He had taken with him the map of the Mountain and the key to the secret door, hoping to try his luck in reclaiming the lost treasure. However, he never reached the Mountain. Instead, he was captured and imprisoned in the dungeons of the Necromancer in southern Mirkwood. There he languished, witless and wandering, until he was discovered by the wizard Gandalf, who was investigating the Necromancer's power. Gandalf tried to save Thrain, but it was too late; the dwarf had forgotten almost everything except the map and the key.

The Legacy of the Map and Key

Before his mind failed entirely, Thrain gave the map and the key to Gandalf, charging him to deliver them to his son Thorin. This act set the entire quest of The Hobbit in motion. Gandalf, who had been searching for a way to challenge Smaug and restore the dwarves, chose his own time and method for handing over the heirlooms, eventually presenting them to Thorin during the Unexpected Party at Bilbo Baggins' hobbit-hole. The map, marked with moon-letters, and the silver key were the essential tools for finding the secret door into the Mountain, without which the dwarves' plan to enter Smaug's lair would have been impossible.

Narrative Role and Significance

Thrain is a figure of tragic loss and a catalyst for the entire adventure. His disappearance and the mystery of his fate underscore the long years of suffering endured by Thorin's people after the dragon's attack. His imprisonment by the Necromancer also connects the dwarves' quest to the larger, darker forces at work in Middle-earth, a thread that Gandalf was already pursuing. Though Thrain never appears directly in the main narrative of The Hobbit, his story is the foundation upon which the quest is built: the lost king, the stolen treasure, and the desperate hope for return. His legacy is one of both sorrow and purpose, driving his son Thorin toward a destiny that would ultimately lead to the dragon's death, the Battle of Five Armies, and Thorin's own final, redeemed moments.