Théoden is the king of Rohan in J.R.R. Tolkien’s The Lord of the Rings.
Théoden rules the horse-lords of Rohan from the Golden Hall of Meduseld at Edoras. When readers first encounter him, he has been weakened and manipulated by the influence of Gríma Wormtongue, an adviser secretly serving the wizard Saruman.
Gandalf helps Théoden cast off that influence. The restored king then leads Rohan during the War of the Ring, including the defense of Helm’s Deep and the ride to Gondor’s aid at the Battle of the Pelennor Fields.
Théoden dies during that battle after confronting the Witch-king’s forces. He should not be confused with Éomer, his nephew and eventual successor, or Denethor, the ruling Steward of Gondor. Tolkien based aspects of Rohan’s culture and language on Old English traditions, which also influenced the names of its rulers.