 The keep occupies the southern corner of Peveril Castle . Construction probably began in around 1176 , instigated by Henry II . Its plan is square , measuring less than 12 by 12 m ( 39 by 39 ft ) , and the parapet is 15 m ( 49 ft ) above the keep 's base ; as the ground is uneven , on the other side it rises 10 @.@ 5 m ( 34 ft ) above ground level . It is smaller than contemporary royal keeps such as those at Dover and Scarborough Castles . Today the exterior is coarse , but originally the facing would have been smooth ; the south @-@ east side , where the steep natural slope prevented removal of the facing stone , gives an idea of how it may once have appeared . A projection in the south @-@ east face of the keep housed a garderobe . As was usual with Norman keeps , Peveril 's was entered through the first floor and was accessed by a staircase . This entrance level would have been a large public room and the basement used for storage . A narrow staircase in the east corner allowed access to the basement and the wall walk around the top of the keep . 
