Rather than a specific race, The Silence are a religious order. Their agents on Earth have been there since before the dawn of mankind, directing human evolution. They use post-hypnotic suggestion to make people who see them instantly forget their existence. They believe that silence must fall when the oldest Question in the universe is asked. It will be asked at “the fall of the Eleventh” on the Fields of Trenzalore, and is hidden in plain sight. As a result, the Silence have tried to stop the Doctor reaching Trenzalore. They used their agent Madame Kovarian to kidnap Melody Pond, and raised her as the Doctor’s perfect assassin. Despite the failure of this plan, the Silence remain at large, determined to stop the Question ever being asked.