Warden of the Keys
Warden of the Keys was a high office of Minas Tirith in Gondor. At the time of the War of the Ring, the position was filled by Húrin the Tall, who gained the epithet "of the Keys". What keys they were, and what other tasks and responsibilities belonged to this office remains unknown. It may be possible that the keys are those that belong to the main gates of Minas Tirith.