A medieval castle had two purposes: it was both a fortification and the home of a lord. The first castles were just earthwork enclosures. Later earth mounds and timber towers were built forming a type of castle called a motte and bailey.

In the context of the UK primary school curriculum (Key Stage 1), a "Castle Year 1" topic is a foundational history unit designed for children aged 5 to 6. Students learn about the basic structural components of medieval fortifications, such as the keep, moat, drawbridge, battlements, and portcullis. The curriculum typically focuses on the transition from the early Motte and Bailey castles, which were made of wood and earth by the Normans in the 11th century, to the more permanent stone structures of the 12th century. Children explore the life of people living within the castle, from knights and lords to cooks and stable hands. The goal is to help young learners understand chronology—how buildings and lifestyles have changed over hundreds of years—and to identify why castles were built in specific locations for defense. Schools often supplement this with "Knowledge Organisers" that define key vocabulary like "turret" and "ramparts" to build the child's historical inquiry skills.