Many prisoners of the Tudors entered the Tower of London through the Traitors' Gate. The gate was built by Edward I, to provide a water gate entrance to the Tower, part of St. Thomas's Tower, which was designed to provide additional accommodation for the royal family.
In the pool behind Traitors' Gate was an engine that was used for raising water to a cistern on the roof of the White Tower. The engine worked originally by the force of the tide or by horsepower and eventually by steam. In 1724–6, it was adapted to drive machinery for boring gun barrels. It was removed in the 1860s.
The name Traitors' Gate has been used since the early seventeenth century, prisoners were brought by barge along the Thames, passing under London Bridge, where the heads of recently executed prisoners were displayed on pikes. Queen Anne Boleyn, Sir Thomas More, Queen Catherine Howard, all entered the Tower by Traitors' Gate.