This keep was built in the 11C by Fulk Nerra to defend the fortified town from its vulnerable south side. It is a solid square construction with two towers, the Tour Louis XI and the Tour Martelet. Inside the keep, the floors of the three storeys have vanished, but three sets of fireplaces and windows can still be seen. A staircase (160 steps) leads up to the top (37m high), from where there is a fine view of the town, the Indre Valley and Loches forest.