This great building stands to-day his monument. The solid masonry walls twelve to sixteen feet thick enclose the vaults formerly used as torture chambers when occasion demanded, the main floor, the banqueting floor and the state floor. The chapel of St. John the Evangelist rises through two floors in the southeast corner, while the low towers at the four corners command the scene for miles. Old Gundulf built well, and completed also St. Peter's chapel and the Hall tower. The other towers with their connecting walls enclosing the Inner Ward were built later, many of them by Henry III. The Beauchamp tower, the Belfry, the Garden or Bloody tower, the Lantern, the Salt tower, the Broad Arrow tower, the Constable tower, the Martin tower, the Brick tower, the Flint tower, the Bowyer tower and the Develin tower, were all built in the wall for purposes of defence, but all have sheltered prisoners from time to time. Within this Inner Ward, besides the buildings already named were royal apartments and a Great Hall of justice (long since destroyed), the mint, which remained until 1810, residences for officers, barracks, etc. Around all this was a second strong wall protected by other strong towers, which was planned and partially constructed by Henry III. Of these towers on the outer wall, St. Thomas' tower on the river—better known as the Traitors' Gate—is the most important. Under this tower prisoners were landed from the river. The space enclosed by the outer wall is about thirteen acres, and around all was a broad moat flooded from the Thames. The importance of the Tower as a fortress diminished with the invention of gunpowder, but it continued to be used as a royal residence, at intervals, until the accession of Charles II. Here Henry III lived and planned great structures; during the wars of the Roses, York and Lancaster held court in turn; Henry VII schemed for greater wealth, and his son was led to defy the Pope while keeping a residence here. But it is with the Tower as a prison that we are most concerned. The roll of the prisoners tells England's history. The petty intrigues of court favourites; the greatness or the meanness of kings; the struggle for power among great families; the truckling to foreign power which brought Raleigh to the block, and the great struggle for religious and political freedom are all set forth in the story of this great prison.