The Clockwork Droids of the SS Madame de Pompadour opened time windows that acted as doorways to the palace. They opened them throughout the life of Madame de Pompadour. They believed that because their ship shared her name, only her brain would do for its processor.
In 1758, Pompadour was thirty-seven, as was the ship. The Droids took it to be the right time to take her head. They invaded the palace. The Tenth Doctor closed off the time windows and convinced them that with no link to their ship, they no longer had a purpose, so they stopped working.