Castles were placed on hills, natural or human-made, so that they could function as both beacons and watchtowers. They were beacons in that they could be seen for miles around, symbols of the power of the local lord. If you could see his castle, you were under his rule. They were watchtowers in that they allowed people in the castle to see an attacking army long before that army reached the castle, giving them time to ready their defenses.

This image is of a 13th-century description of a battle at Lincoln Castle in England on May 20, 1217. French attackers are driven off by archers high atop the castle walls. Castles were surrounded by a wall for protection. A gate in the wall let the peasants in when they fled an attack. Inside the wall was the central castle with its high towers. If attackers made it over the wall, they were met with various attacks from within and above. Most large castles were successfully defended from attack.

Castles were not just fortresses. They were the homes of the noble lords. Each castle had a great hall, like this one at 11th-century Stirling Castle in Scotland. Here the lord and his family ate and were entertained by musicians, singers, and dancers. They also welcomed guests (maybe even the king himself). The great hall was also the place where the lord and his knights met to plan for war