Warden of the Keys
From Tolkien Gateway
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 is possible that the "keys" were the keys tho the gates of Minas Tirith.
