The major theme of The Hobbit is the quest, one of the oldest themes in literature. As a scholar of ancient languages and literatures, Tolkien would have known the theme well through Greek and Norse myth and Old- and Middle-English poetry. The quest theme is central to the story of Beowulf, the Old-English epic about which Tolkien published an essay of lasting scholarly significance in 1937. The quest story best known to modern readers is probably the Arthurian legend of the Holy Grail, in which a knight ventures forth in search of a sacred cup (the Grail) that he brings back to restore power to his king and, thus, improve the welfare of the kingdom. The Grail story is an important sub-plot in the middle English poem Sir Gawain and the Green Knight, which Tolkien edited with his friend E. V. Gordon and published in 1925. Given that a cup and the Grail are similar objects, it is interesting that it is a cup that Bilbo Baggins steals from the dragon's treasure when he first descends to Smaug's lair in Chapter 12.
The quest theme is related to two important features of The Hobbit and other works in which it occurs. The first of these is the journey plot structure. The protagonist or main character who embarks on a quest must physically go somewhere; his search involves travel, usually in a circular route such that he returns home with the object of his quest. The journey allows the main character to encounter various characters and circumstances that are unfamiliar and even threatening to him. Thus, novelty and suspense are built into the journey plot. Bilbo, for example, encounters Goblins, Wargs, elves, Gollum, and Smaug the dragon on his journey to help the dwarves retrieve their treasure, and he travels well beyond the hobbit-lands through Mirkwood and the Misty Mountains to the Lonely Mountain. Along the way, he escapes death several times, undergoes the privations of hunger and bad weather, and ultimately sees combat in the Battle of Five Armies. None of this would have been possible if he had stayed at home in the safety of his hobbit-hole. The structure of a journey plot is often described as episodic, meaning that the protagonist moves from scene to scene (or episode to episode) in a rather simple linear fashion; there is no complex interweaving of the various characters he meets throughout the story. This is generally true of The Hobbit: It is not until Chapter 15 that the various groups of creatures Bilbo encounters on his journey converge on the Lonely Mountain in what becomes the Battle of Five Armies.
The second important feature related to the quest theme is in the character development of the protagonist. In most quest stories, the physical journey serves as a metaphor for the personal growth of the questing character, for whom the quest is often the fulfillment of a personal destiny. As the protagonist travels physically