When you look at these early 12th century square (or rounded-off) keeps with modern eyes, you find it hard to believe that it could serve as a family’s home. Most of the space was used for storage, since the keep was designed as a siege refuge. And the rest of the space was devoted to two big rooms: the hall and the chapel. Where did they live?
The answer lies back in Beowulf’s time, when a typical Germanic tribal settlement consisted of one large (barn-like) wooden hall and a number of cottages around it. In order to survive, a tribe needed a central ruler and his council, the ones who would make high-stakes fight/flight decisions. They had to be men, since that’s who hefted the spears, although women were a significant part of hall defense, in addition to doing all of the support work and bearing the next generation. Germanic communities never treated women in a demeaning way; for their time, they were noted for feminism. But the king and his council, and his closest band of warriors, needed to live and think as a family.
So the king was expected to maintain a hall large enough to be his own family’s home and also meeting space and communal living for as many men as possible. In peacetime, many of them split their time between the hall and their family’s cottage. When they stayed over in the hall, they didn’t expect a guest room. The king and his wife had a private chamber, usually right behind his chair (no need to call it a throne, it was the only chair in the room). Their children slept with them or in small anterooms with servants.
Everyone else slept in the hall, wherever they wanted to bunk down. In Beowulf, there’s a line where the servants open chests along the walls and get out pillows and blankets. The benches and cleaner sections of floor became beds for the resident guard troop (and in that case, the visiting Geats).
That had been the standard for centuries, so it was natural for them to design castles around one large hall. The baron still had a private chamber, still usually right behind his official chair, sometimes merely curtained off, sometimes with a separate room. In larger keeps, there were big upper rooms where we should imagine a large number of people sleeping on the floor or on straw mats. But in smaller, simpler designs, the knights who stayed over at the keep just slept in the hall. They were usually unmarried, so had no family home. Servants lived outside in the village or slept in the kitchen or storage rooms. Nobody expected privacy, and nobody got it. (If privacy mattered oh so much to someone of this time, the monastic life was always an option.)
It also felt perfectly natural to castle-designers to take some of that precious floor space and devote it to a chapel. All other group meetings, from holiday drama to court proceedings, took place in the hall. In some ways, the barrier between civilized men and barbarians was to devote some space to purely spiritual times. Life was hand-to-mouth otherwise, and it was often violent. The difference between men and animals was that men cared enough about their invisible souls to set aside a symbolic space where nothing else could be done, only meditation, song and rituals for the soul.
Chapels were smaller than halls, but they were sometimes more grandly decorated. Both rooms were the beneficiaries of each new improvement in architectural methods: they were the first to get vaulted ceilings, glass windows and chimneys.