In a Motte and Bailey castle, the "keep" (also known as a donjon) is the fortified tower that serves as the refuge of last resort and the primary residence for the lord or noble. It is located on the highest point of the "motte"—a large, often man-made earthen mound. The keep was designed to be the most secure part of the fortress; if the lower courtyard (the "bailey") was breached by attackers, the defenders would retreat up a steep bridge or staircase into the keep. Early keeps were built of timber, but many were later replaced with stone as siege technology advanced. Inside, the keep typically had multiple floors: the ground floor or basement was used for storing food, water, and weapons; the middle floor housed the "Great Hall" for banquets and legal business; and the upper floors contained the private sleeping quarters for the lord’s family. Beyond its defensive utility, the keep served as a powerful political symbol, looming over the local landscape to remind the population of the ruling noble's authority and wealth.