The inhabitants of the castle would vary greatly depending on the time of year, whether it was a time of peace or war, and whether the lord was in residence. The lord would not live in the castle all year round but visit it as part of a circuit along with the other estates that he owned.
When the lord was in residence the castle would be a hive of activity. It would become the home of the lord and his family and their servants, which would have included cooks and serfs to wait on the lord.
In times of peace and in the absence of the lord the castle would have been looked after by a Constable and a garrison of probably not many more than five or six men. They would ensure the general upkeep of the castle and protect it from marauders.
[Original author: Miranda Greene, 2002]