Themes from Old English literature, and specifically from Beowulf, shape the ancient world Bilbo stepped into. Tolkien, a scholar of Beowulf, counted the epic among his "most valued sources" for The Hobbit. Tolkien was one of the first critics to treat Beowulf as a literary work with value beyond the merely historical, and his 1936 lecture Beowulf: the Monsters and the Critics is still required in some Old English courses. Tolkien borrowed several elements from Beowulf, including a monstrous, intelligent dragon. Certain descriptions in The Hobbit seem to have been lifted straight out of Beowulf with some minor rewording, such as when the dragon stretches its neck out to sniff for intruders. Likewise, Tolkien's descriptions of the lair as accessed through a secret passage mirror those in Beowulf. Other specific plot elements and features in The Hobbit that show similarities to Beowulf include the title thief, as Bilbo is called by Gollum and later by Smaug, and Smaug's personality, which leads to the destruction of Lake-town. Tolkien refines parts of Beowulf's plot that he appears to have found less than satisfactorily described, such as details about the cup-thief and the dragon's intellect and personality.